Forgive my ignorance when asking:
What is the difference between biphobia and homophobia? One is toward bisexual people and the other homosexual. But homophobic responses can be made to bisexual individuals. It has the same root of "different" to not-so-nice people.
So would the way of dealing with homophobia be similar to biphobia?
Regardless: if they're an ass, to hell with them. They're not worth your stress. If they have no sense, you can try and correct. Good luck!