That one man's experience is the same experience for almost all gay people who feel the need to hide their preference. Like I said, there are a number of reasons they're afraid to go public.
For certain, there are gay athletes, and have been all along. Rock Hudson was gay, died of AIDS. An athlete might fear his teammates would bully him or worse. Hudson was a sex symbol that women swooned over. His career would have turned to shit if he came out. I'm sure his friends knew, though, and kept his secret.
I knew a guy for over ten years before he told me he was gay. He thought I'd reject his friendship because I am rather conservative. It didn't phase me one bit. I liked him fine before I knew, and he's still the same friend I always had after I knew.
In your case, I can see your friends not wanting to be open with you. In your one case, until 30.
The thing about my friend is I wasn't pissed he was gay, but that he lied to me about it for 10+ years.
Too many good people are living that lie for no actual good reason. That's why it is big news about the football player or the former Nets center. If they are accepted, as they should be, more people won't have to live the lie.
I assure you that if you used a public shower, you showered with gay guys. You weren't harmed by it, and it really wouldn't matter if you knew. They didn't rape you or whatever it is you fear. They're as normal as anyone else, in reality.