It is interesting that you define Mercury as homosexual. Many overlook that he had an open relationship with a woman for years and years.
Anyway, I've been in and out of the gay community since college (20 years ago). Like you I've come across quite a few who were sexually and physically abused (mostly physical/mental stuff). There's a lot of guilt with gay men. I find the opposite with lesbians. There's a great deal of hostitliy there - especially towards men - maybe for the same reason. My sister is gay, and she's offended by just about anything remotely sexist. She holds men in such low esteem, I find it unpleasant to be around her.
Yes, there seems to be a veneer of "gayness" around male homosexuals that make them look shallow where really there is - lake you said - a mess.
About 15 years ago my therapist gave me an article on a socialogical reason for male homosexuality. The study found that a sizeable (I do not remember the numbers) amount of gay man are the youngest male in a family with mulitiple male children. It's a weak link/pecking order/runt/momma's boy situation. Four gay men that I know fairly well fit this description - and I don't live in the gay community anymore.
I found after years of being gay (sounds funny doesn't it) that I was reenacting my abuse. I let anyone and everyone do what they wanted with me. If they got off that's all that matterd. I didn't or hadn't found anyone I wanted for more than sex or friendship, never both.
The straight life isn't much better because when you tell your partner you've had same sex relationships they pretty much run away. I tried hanging with the neurotic bixeual folks, but nobody will have anything to do with them. They are sexy in the movies but the reality is much different.
I'm pretty much a neuter now because I'm unable to have a relationship that does not end up somewhere south of hell. I understand what you are saying - I had a lot of fun/drama when I lived in D.C. back in the late 80s'early 90s. I consider myself extemely fortunate that I'm not HIV+. Matter of fact, it's an fn miracle that I've never had any STDs.
There's a tremendous amount of guilt in both groups.