Didn't Freud prove that most people would be bisexual if it wasn't for religion, society, shyness, lack of imagination etc etc? I totally believe that, but I'm biased because I'm bi. I don't believe in limiting yourself just because of rampant ignorance in the world.
About it being a choice, I'm not really certain since I'm the only bisexual man I know in real life and haven't been able to talk about mutual experiences with anyone. I've talked to a lot of bi women though and they've had pretty much the same experience as me, just the other way around - for the first few years of puberty they've liked only men, but after that they started noticing women as well and said to themselves "fuck it, I like them as well", so they went with it. The straight men and women I've talked to refuse to even acknowledge that a same-sex relationship involving them is even possible, but I don't know whether that's true or they just fear them because of societal pressure.
Anyway, I don't see what you are trying to prove with your little rant, I don't think it's the world's business who you sleep with. It doesn't matter whether you are bi, straight, gay or any of the cornucopia of sexualities, it doesn't make you any more or any less of a person.