On my last point. I made it because I am bi and have been in a het-relationship for decades now. While you’re right that homophobia & biphobia keep people closeted (because conformity means survival in a world filled with people who become outraged over a hint of homosexuality) + the raw statistics of a majority of the population being straight means that bisexual people often fall in love with someone of the opposite sex. Those people are just easier to find and more open about expressing interest but that doesn’t change anyone’s sexuality.