Because heteropatriarchal culture devalues female sexuality, and especially female sexuality that doesn't please men, it can be really hard to notice the biases we come to accept as the norm when we reject heteropatriarchy. By that I mean, when you start listening to your own queerness (and there's nothing wrong with calling yourself queer rather than bi, especially if your attraction to men was the exception rather than the rule), it can be really easy to go too far in the other direction, and become resentful of those who don't subvert all the same norms. I see it a lot with lesbians saying they don't want to date bi women, because bisexuality is an 'experiment' or 'phase' or 'for men' or they've been 'contaminated'. That sort of rhetoric is biphobic. The fact that you're questioning if you're biphobic tells me you probably aren't - -at least not consciously or deliberately. But you might want to examine why you're threatened with the idea of dating someone who's bi, especially if you're also poly. We're all just doing our best and learning and growing; queer people need to support each other as we go through that process of taking stock of, and then unlearning, our own prejudices.