So just to set a scene I am a gay male and I nowadays nearly exclusively play gay male characters. I very occasionally play female characters but when I do I will generally go for someone 35+.
I am not a big TS hound, but I am happy to go there if there is some element of story involved. However, TS involving female anatomy (either as or with) is a squick to me, hence playing older women as this generally (sadly, wrongly) eliminates most of the attention I don't want to deal with.
Before I came to MUSH I played a lot of MUD games, especially RPI MUDs (particularly Harshlands and Shadows of Isildur) which happened to be set in medieval fantasy settings (Harn and Middle Earth).
On both of those games (much more so on SoI) there was a policy of strongly discouraging nonheterosexual characters, on the basis that they did not 'fit' within the settings. This basically took the form of a staff member pulling you aside before approving you and making it clear that if you were discovered to be gay IC, it was basically open season for you to be subjected to any level of discrimination (up to and including your character being outright murdered) and that no complaints about it would be entertained.
As you might imagine, this had a chilling effect on anyone rolling up anyone that was nonheterosexual and of the few attempts that I did see (including the only gender non-conforming character I ever saw rolled up there) most ended up getting brutally tortured and murdered almost as soon as they were discovered. I will say that I generally played on 'team evil' there, so I am not sure if this was less pronounced in the more heroic areas of the game, but it was made clear that it was discouraged and opened you up to any level of IC discrimination wherever you played.
So, I will say that following that experience, coming to MUSH it was a breath of fresh air even for it to simply be non-controversial to app in as a character that reflected my OOC gender and sexuality. I realise that this is an incredibly low bar to set but it is genuinely where I started out.
I have still had some pretty shitty experiences, my most recent one was being accused (since I was at the time playing a female character) that as I was a gay male this was 'obviously' part of some fetish I had about luring unwitting straight boys into having TS with my character. This despite the fact that my character was single, not engaged in any romantic RP and not seeking any romantic RP.
I will say that generally (generally!!) I find most MUSH people to be really cool, welcoming and friendly people and it is very seldom I feel uncomfortable about being open and honest both IC and OOC about who and what I am. Reaching out to other LGBT characters (where you can find them) tends to find you a group of pretty cool people wherever you go, honestly, and I have been lucky to meet a few people who have actually become close RL friends of mine through MUSH.
I will still sometimes feel like I am getting a strange vibe off of a channel, or an individual or a clique, but rarely anything I can put a finger on and honestly as a gay person there is an element of that which is just sort of the background noise of life. This tends to be much more pervasive in spheres where there is more of an alpha male, or very very heteronormative theme (looking at you, werewolf) going on, honestly.