You make a logical leap which I do not make.
We agree that sex between two men should not be acceptable to Christians. That is our common view of the teaching of Scripture and the Tradition of the Church.
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You state that "loving is for all relationships in Christ's teaching" and conclude that we should not even discuss loving relationships outside of ones that are acceptable within the Church.
I will not jump to the judgment that two people of the same sex cannot love one another. I will not jump to the judgment that a married person cannot love someone to whom he or she is not married. I will not jump to the judgment that there is no love between those who have a sexual relationship when the two are not married.
All of these are sin. All these actions will be judged by Jesus when the time comes. However, it not for me to judge those who do not accept Jesus and Scripture. It is not for me to judge whether they are in a loving relationship. Even with regard to fellow Christians, am I really to judge that there is no love between two people because they sin sexually? If I (and our Church) had this attitude toward all sinners, there would be few left who were acceptable to the Church.
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BOTTOM LINE
When two folks have examined their relationship and tell me that they love one another, I believe them. Should I really ask them for their marriage certificate? They may be in a relationship where they sin every day. Their presbyter should be clear with them that their sexual activity is sinful. But it not for me to say that they are not in a loving relationship, because that is not possible. Of course, I am certainly willing to give my opinion of what Scripture teaches and to share what the Church teaches to such a person (if there is reasonable opportunity and I believe that me stating my view will help this person come closer to Jesus).
Should I really tell such folks that they do not love one another because Scripture says that such love is impossible? IMHO, that approach does not represent good pastoral care, good fellowship or good discipleship.
In the end, for me, we should about bring folks to Christ and helping the less fortunate among us. We are not appointed to be Christ's policemen.
To put it another way, if I firmly proclaim God's truth and the person to whom I am speaking runs away, I do not expect a pat on the back from Jesus, and congratulations to his good and faithful servant. Rather, I expect that the Holy Spirit will prod me with regard to how I might have shown more love to the less fortunate among us.