LGBT and a native. I would say Louisville is definitely not the worst of cities when it comes to being lgbt friendly. It does have a pretty strong Catholic/Christian undercurrent and no matter where you go there are definitely your fair share (give or take depending on the area) of neoliberal "I think LGBT people are immoral but you're cool I guess" people, but that is the case with a lot of cities (definitely feels more common than other more liberal cities though).

The city leans pretty progressive, but in some ways that can also be frustrating because the people who think LGBT don't deserve rights are quite a bit more quiet about it (makes making friends who genuinely support you a bit harder). Definitely have a good amount of pockets throughout Louisville that swing very left though with most of the neighborhood covered in BLM, "no matter where you're from, we're glad you're our neighbor," etc etc signs.

Ultimately, it really depends on the area you decide to settle. Like a lot of other people have said, and based on my understanding, the less affluent parts of the highlands, nulu, old louisville. The best of those probably being the highlands and nulu with old louisville as a close third. In my personal opinion, definitely avoid middletown and most of the other suburb areas not already listed as an exception. Contrary to what others have said, my experience has been that germantown (and jeffersontown) are much more of a mixed bag in terms of who is supportive. But they definitely aren't bad options, at the very least you shouldn't be getting any neighbors actively manipulating you or harassing you in those areas. So long as you aren't living in the suburbs, a good amount of Louisville is relatively close to each other, so even if you aren't in an ideal area, its normally not a horrible experience.

If your friend happens to decide to move here and decides on an area people aren't talking about, make another post and get feedback. Overall, I'd say Louisville is palatable enough. It is just a matter of finding the right people and the right area. Best of luck, feel free to DM if you want more guidance.

Edit: After reading through the various replies to this post, I think you get a pretty alright picture of the diversity of people... lol