Unfortunately, it does exist, despite your apparent lack of belief that it does. That's just reality, and from here on out I'll be removing comments or posts that promote it, minimize its harms, or deny its existence-- including comments like the ones you made on the other post (and this one). It sounds like you may not have had much experience with it personally. However, I've talked to many other bisexual people who have been affected by it, and I'd like for this sub to be a welcoming place for all LGB people, not just ones who aren't affected by biphobia (or homophobia, or any particular type of experience that happens to a subset of LGB people).

Furthermore, one doesn't have to be bisexual in order to know that biphobia exists. It's an observable phenomenon with a clear definition and there are many examples of it happening. It's also worth noting that bisexual erasure negatively harms homosexual (L/G) people as well, pressuring some bisexual people to be in the closet about their bisexuality and claim that they're gay/lesbian when they're not.

If you're not sure what I mean by biphobia, I gave you a clear example of it in this post. However, if you're looking to engage in a debate about biphobia (or a debate about anything, really), this is the wrong sub to do it on. I suggest s/LGBDroptheT, or when the mods eventually open it, s/LGB.