Heck, I think lots of WOMEN are bi that don't realize it yet... it's just easier for women to be intimate with other women without raising alarms... men can't hug each other, even.
I do believe a lot of homophobic people are really just trying to hide attraction. I know I was... I used to be a burning rage of fire and doom against fags, until I reconciled me and my attractions to both the same sex, and the third gender.
Frankly, I think most people are bi until they prove otherwise, and there's a pretty big gray area between the two extremes of ABSOLUTELY STRAIGHT and ABSOLUTELY GAY, filled by people who may be 99% straight, or 95% gay, and just haven't seen the right hottie to trigger a brief bit of arousal. Sexuality is, in my opinion, determined by attraction rather than experience. Bi-curious is a ridiculous word. Just be bi, maybe a lot closer to the straight end of the scale, but bi.
In a world where people are confident about their bisexuality, relationships would be a lot easier, I think. I feel sorry for men who are conditioned by society to be homophobic and always ignore any underlying things, creating tension just for the sake of social norms based on gender stereotyping.