BakaTulip
This was something that dawned on me at AnimeNext yesterday. I'd met up with my girlfriend there for the first time face to face and we were walking around with our arms around each other and nuzzling and cuddling when I saw someone with a shirt that says "I'm not a lesbian but my girlfriend is." I pointed it out to her and said I wanted it but then something dawned on me. I'd seen MASSIVE ammounts of rainbows there and tons of people wanted to take pictures of me and my girlfriend (though we were highly out of character for our costumes) and I began to wonder. Is there something about anime (beyond simple yaoi and yuri) that appeals to homosexuals and draws them to conventions or is it just a coincidence. Most places you go, most of the time 10% of people are gay but it felt like more than one tenth of the people there were gay and almost everyone was okay with it. I don't think we got a singl strange look.
Unfortunately, there may be a more prosaic explanation for your experience: anime is, in a lot of cases, something that young people like. Sure, you have your 40 year olds who've been collecting and watching since Speed Racer, but it's really infused itself into youth culture. It would be strange for a majority of youth not to know what anime is anymore.
That translates to more open-mindedness. Certainly there are plenty of youth who are closed-minded, but psychology will tell you that young people are far more open to change and only tend to become more conservative later in life. People get set in their ways and stop thinking that abnormal things can become normal.
Anime itself is a draw to youth because of its strangeness. And we can go into how bisexuality may be a fad and how open Japan appears to be to alternative lifestyles and so on and so forth.
But that's just my thought.