I honestly think the best thing to do is too ignore it, I’ve noticed most “heterophobes” are just trolling and might not actually be “heterophobes.” I put “heterophobes” in quotations because I don’t feel like it’s a good term to use. “Heterphobia” at it’s worst is some rude comments, while homophobia at its worst can mean death. Using the word “heterophobe” is a bit like saying that straight people suffer for being straight, when we really don’t. If someone thinks all straight people are homophobic I would point out that if we where all homophobic the lgbtq community would not have rights, because straight people naturally outnumber the lgbtq community. Then leave it at that.