If you are lonely that might be because you are not easygoing, or you criticize people too quickly(as you just did). If you were just unusual, as everyone else is, you would have friends and wouln't feel lonely
Why should it bother me? Sex is universal, we all do it. It's certainly not information I desire to seek out, but I'm not sure why knowing what goes on would be so terrible.
I see a difference between hiding your identity and not loudly shouting about it in public. Personally, I quite enjoy recreational drugs and my close friends know that but my coworkers don't and that's fine. Why is sex so much different? am I bad for being "closeted" about my drug use?
edit: don't mean to imply being queer and using drugs are the same or anything. Just an example of "thing you personally are okay with but the wider society might judge you for"