So I'd be curious if a Roman Catholic could tell me what's going on.
Sure. There are two things that overlap. One is the desire on the part of feminists in wider society in the world to eliminate sexist language.
The second is the desire of the Church to be correct in its words.
People who are ate up with politics will whinge that the Church is "giving in" to...whatever. Other churches do that. The Catholic Church operates differently for reasons of structure.
So, when the Bible was retranslated, the wording of pronouns was looked at. Where the Hebrew or Greek words are not forcibly masculine or feminine, or where the people referred to are referred to collectively, the traditional linquistic convention of translating ambiguity with the male pronoun is discarded, and the inclusive pronoun is used. "They", instead of "he", "us" instead of "us men", where what is intended is humans, not males.
The Father, Jesus, the Lord - these are "He".
The same convention applies in the liturgy and other materials.
For example, the prayer, the Nicene Creed, has a section that is traditionally rendered as "for us men and for our salvation, he came down from Heaven". Today, this can also be said "for us and for our salvation, he came down from heaven".
Is there a difference here? Theologically, none. "Us men" in the original formulation clearly, unambiguously, and certainly includes women. It means "us humans". But saying "humans" is just weird, and unneccessary "us" says the same thing as "us men". If we insist upon "Us men", why are we doing it? Either stubborn traditionmongering, which the Church is trying to get away from, or a stubborn chauvinism, which is not theologically correct. We can say "Us men" for traditional reasons, or to make a statement that it's fine - and that's ok. But if we want to make a theological point that there is a difference, then the authority of the Church is staring us down and saying "No, you are wrong - this language does not mean that men are superior to women in this prayer. And there is no THEOLOGICAL issue here. You are taking an issue of politics and comfortable language and trying to make it a theological issue, but you have no authority to do that, and you are wrong."
Another example. the Christmas Carol: Hark the Herald Angels Sing, has a verse that says: "Born to raise the sons of earth, born to give them second birth". The new hymnal version reads, instead "Born to raise us from the earth, born to give us second birth".
From the perspective of accuracy, the new words are correct. The former language appears to be limitative to men. Of course it wasn't INTENDED to be, but in an earlier age women were effaced and did not take offense. Today, some do, and many note the issue. There is no reason for the Church to take a stand in favor of some traditional words of a Christmas carol. The new lyrics are more theologically correct. Of course, if we want to, we can still sing the old words. It's not WRONG to sing the old words, but it IS wrong to stubbornly insist on the old words in preference to the new words, because when the old words which were casually and unintentionally male, from a time when that didn't matter, are defended on some sort of false theological ground, that it's IMPORTANT, for some reason, to insist on the masculine forms when they do not, in fact, have theological meaning - well, that INSISTENCE on the male where it is neither necessary nor implied, DOES have theological meaning - and that theology is bad. The old habit was just that, a habit, and not offensive, in its time. But where it gives unnecessary offense, to insist upon it today for theological reasons when none exist and the real motivation is political and stubbornness - then it's important for theological reasons, NOT to let that spirit prevail.
Traditional masculine language is not a problem in itself. INSISTING on it when it is not necessary IS a problem: it's bad theology and forces a theological inaccuracy.
Naturally, this approach will not be understood by or acceptable to non-Catholics for whom male chauvinism is intended by God. Nor the lack of political motivation will suffice for the politically motivated.
The Catholic Church does what it does for reasons that really don't have very much to do with American politics and sensitivities. America is just one of many Catholic countries, and not a particularly influential one in the Church either. Brazilians and Mexicans are not butthurt about these linguistic matters - the church is seeking accuracy, not appeasing political spirits. Where it matters, in America, this is visible and becomes part of the American political zeitgeist, but the Church doesn't have American politics in mind when it does these things.
In short, whatever your hobbyhorse is, what the Catholics are doing will disappoint you. We're not doing it for any of the reasons you think, we're not doing it the way you think we are, and what comes out of the Catholic process is more theologically accurate.
The Swedes, by contrast, are just collapsing in the face of politics and have ceased to believe the religion.
Catholics haven't changed any beliefs. They have cleaned up language to make the truth more accurate to the faith and to the originals.