I'm a conservative Christian. I believe that homosexuality is a sin. The one co-worker who I knew was gay, I told him that straight out. I also continued to work with him, and kept him as my friend. (Lots of my friends are sinners. For that matter, so am I.) I continued to be someone he felt he could confide in - he'd come talk to me when he needed to gripe, because he knew he could tell me sensitive stuff and I wouldn't burn him with it.
Now here comes company diversity training. It includes LGBTQ stuff. If it says "treat people professionally; whether they are LGBTQ or not is not something that affects how you treat people in the office", well, I'm fine with that. It's what I do anyway.
But if the diversity training moves on to "you should have a positive view of gay marriage" or some such, well, that's forcing a political position on me.
Note well: I have never experienced that. But I think I've heard of such things happening (and no, I can't document even hearing it).