I don't think that understanding of sin is exclusive to the EO. I think all who accept original sin (as Lutherans do) would agree with you, though maybe with subtly different shadings.
Regardless, I like what you've said about sin as a disease, especially given my personal experiences with chronic disease, which one doesn't cure but contain.
In the West in general there is more emphasis on the forensic aspect, particularly if we look at Anselm of Canterbury or some aspects of Calvinism, or even as far back as St. Augustine of Hippo, but in the case of Augustine we still see a lot of balance. And indeed the reformed tradition itself is not as legalistic as it looks, nor is Roman Catholicism. The East, for that matter, does not completely reject a forensic interpretation of sin, indeed, if we look at St. John Chrysostom, I think we see an example of an extremely forensic approach to sin, which nonetheless also acknowledges its diseased state, whereas if we were to look at someone like St. Basil, we would see what might seem to be the opposite view, but the Eastern tradition is a synthesis.
The real tragedy is the Great Schism that separated Eastern and Western Christianity, in a process that took several centuries, which is often dated to 1054, but began earlier and was only really finished with the Fourth Crusade, the disastrous Council of Florence and the Union of Brest-Litovsk. Now prior to this, in the fifth century that separated the Eastern churches into three bodies (briefly five, when the Maronites broke away from the Syriac Orthodox and existed as their own church before enthusiastically entering into communion with Rome during ghe crusades, and also the extended schism between the Armenians and the other Oriental Orthodox), not counting shorter duration heresies, but historically, the lines have often blurred between the three Eastern churches, and there have been times when they have essentially been either united or close to it. In general, the divisions were often more about language, ethnicity or geography than doctrine, with some exceptions (such as the Syriac speaking community of Maaloula, Syria, which is a member of the Antiochian Orthodox Church, which stopped using Aramaic or Syriac in the 13th century in its liturgy; they could have become Syriac Orthodox, but instead retained their Antiochian identity; now, since 1991, in the Middle East, there is intercommunion, if not full communion, between these churches).
But the effect of this tragedy is that beautiful ideas from the West stopped migrating to the East, except in occasional bursts owing largely to “modernizing” Russian czars and other potentates, who often did more cultural harm than good (but the beautiful music of the Russian, Belarussian, Ukrainian, and other Slavonic churches, and later, the emegence of the Russian and Ukrainian musical tradition, and its exceedingly great composers such as Tchaikovsky and Prokofiev, is largely the result of Italian Baroque composers being brought to Ukraine in the 17th and early 18th century to teach tonality and four part harmony, which resulted in a proliferation of beautiful new styles of chant and the gorgeous music of these churches). Stained glass windows are another great Western idea that never took off in the East; in the West, one could argue they serve a function analogous to the Icons in the Orthodox churches. And likewise, in the West, while a tradition of Iconography analogous to that of the East did exist in the Romanesque and Gothic periods, it died off in the Renaissance and Baroque, although it was partially revived in the 19th century in the restoration of Anglican cathedrals that had been ruined by iconoclasm previously.
Beyond aesthetic ideas being stuck on one side of the divide or the other, the movement of theological ideas also became, for want of a better word, severely stalled. The West had to wait until John Wesley to get an explanation of the Eastern doctrine of salvation through Theosis, and sadly the Methodists did not preach this central Wesleyan doctrine as much as one would hope after his death, and some that did distorted it into something else. Other ideas, like the theology of Gregory Palamas, were completely unknown in the West until recently, but Palamist theology is brilliant. Thanks to the Jesuits, the East had slightly more access to Western theology, but this was often completely mistrusted; Lutheran theologians likewise who attempted a dialogue with Patriarch Jeremias II of Constantinople failed to achieve any meaningful theological consensus; simplistically, one might blame this on stubborness, but I think neither party fully understoof ehat the other was saying.
Some things that Martin Luther himself said are very confusing and can seem off putting, especially at first glance, for example, his exhortation that we should “sin boldly”, but while lurking before registering I read a post by
@MarkRohfrietsch which explained this in a manner that makes sense.
There were good theological ideas in all directions. The East had Gregory Palamas and Dionysius bar Salibi, and the West had Thomas Aquinas and John Calvin.
On occasion, when a meeting of the minds did occur, the results were always wonderful to behold, for example, Jan Hus, the Czech reformer and martyr, who is my favorite reformer, who I personally think sparked the Reformation that later erupted thanks to Martin Luther, in that it was Jan Hus and Jerome of Prague who first planted the seeds of dissent towards the problems that the Roman Catholic Church was having, at that time, due to corrupt leadership (problems I think were largely fixed in the centuries to come, starting with the Council of Trent, but without the Reformation, the Roman church could well have continued its dire stagnation under the likes of the Avignon Popes, the Borgias, Julius II and Leo X).
Some people attribute the reformation to the Waldensians, or the Lollards, or Wycliffe, but they were not as central or as poweful as the Czech reformers; the Reformation became a secured fact when the Elector of Saxony embraced Lutheranism, and as many of you may be aware, Saxony and the Czech lands are directly adjacent (the Moldau river which flows majestically through Prague descends through a beautiful valley, becoming the Elbe as one enters Germany and flowing with equal majesty through Dresden, the capital of the old Kingdom of Saxony before the unification of Germany under Bismarck and the Prussians).
The Lollards were extinct and largely forgotten by that time; Wycliffe’s remains were desecrated and thrown in the Thames post mortem by outraged Norman bishops, furious that he would have the temerity to translate the Bible into English, and a campaign of Damnatio Memoriae by the English government resulted in him being not a very well known figure by the 16th century; rather, the appreciation which he deserved followed the Reformation. The Waldensians, who I love, likewise were out of the action; they were in Vaudois and then Piedmont, and subject to continual genocide of the worst sort until finally the Reformation reached Switzerland and they found asylum. But alas, their theology, which had some good ideas, was displaced through homogenization with Swiss reformed thought. And the Swiss reformation occurred because of the fuse lit by Luther, leading to the dynamite of discontent in the Czech Republic, Saxony and elsewhere in Northern and Alpine Europe, which ultimately was planted by Jan Hus and Jerome of Prague.
And the thrilling fact is that Jan Hus and Jerome were prompted to Reform, because the Czechs had been Eastern Orthodox, until Austria conquered their country and forcibly converted them to Roman Catholicism; not the Eastern Catholicism of Eastern Poland and the Carpatho-Rusyns, Ruthenians, Lemkos, Western Ukrainians and some Lithuanians, but the full Roman Rite, which meant liturgy in Latin and not the vernacular, and no more shared chalice of the Blood of pur Lord, but communion of one kind only, and a vastly different approach to theology, and even church architecture. So Jan Hus and Jerome of Prague started the Reformation by attempting to re-implement the most obvious and important parts of Eastern Orthodoxy that their country had lost when it was conquered by Austria, while retaining those aspects of Western Christianity that people had come to accept.
And today, the Moravian Church and its relatives in Europe and America have survived, despite near genocide, and the revived Czech Orthodox Church venerates Jan Hus and Jerome of Prague as saints and holy martyrs. Also, John Wesley’s contact with the Moravians may well have been a catalyst for his interest in Eastern theology, which in turn led to his teaching of Theosis (as Entire Sanctification), his stress on the importance of fasting not only on Fridays, which is universal, but Wednesday also, and many other aspects of his life and that of his brother Charles (also including frequent Communion).
So, every time East meets West, the results are spectacular. With regards to the sad issue of homosexuality, by stressing the equality of sexual deviation in the sight of God and emphasizing the benefits of heterosexual monogamy, and of Holy Celibacy (and absolutely rejecting the idea of “Asexuality” which is being appropriated as a part of “LGBTQIA+” - I dread to think what the plus represents), and the idea of sin being a disease as much of an offense against God, and also stressing the universal nature of sin among humans, in that contrary to Westboro Baptists, homosexuals, while sinning in that respect, are by no means the worst or most vile of sinners; they are not Satan or demons, and do not deserve to be demonized for the particular passion that afflicts them, but the sinful nature of homosexuality must be recognized), we can move forward.
The remaining Western churches faithful to Scriptural doctrine on human sexuality, like the LCMS, the PCA, the ACNA, the Mission Province of the Church of Sweden, the SBC, the Norwegian and Polish Old Catholics, the Roman Catholic majority (and also officially), the UMC for the moment, and especially, the faithful provinces of various churches which emerged from missionary work in Africa, the Americas, the South Pacific, and other places, the so-called “Global South” in Anglican circles, but a group equally important and influential in nearly every church, can make their message more articulate by using an Eastern soteriology to explain it, and also attacking adultery with the vengeance that that family-destroying sin requires, and hopefully, through prayer, those churches which have fallen into error regarding sexuality can be moved by the piety of the East and the continual martyrdom of Eastern Christians, and now Western Christians as well, by Islam, Communism, Hindu Nationalism, Buddhist militants, and so on, to repent. In my stint in the UCC I was not able to get very far with many of my colleagues on this point, but the United Church of Christ is one that really greatly requires our prayers; it could be gone in a decade, or else apostatized to Unitarianism, and that would be a tragedy.
I thought I would end this longish post with this Byzantine style icon depicting John and Charles Wesley: