how are they complaining about biphobia/erasure (legitimate issues) while doing shit like this????? HOW

Bi-erasure is more harmful to homosexuals than bisexuals because it legitimizes the idea that homosexuals can be "converted". Biphobia just tends to be insults/stereotypes like "bi people are hoes" and never results in violence (though bi people are subjected to homophobic violence, which some people call "biphobic" eyeroll). So bi people aren't subjected to the negative effects as much as homosexuals, who are specifically targeted. They do suffer when homophobia increases as a result, but it's not like their only other option is to be celibate if you know what I mean. Basically idiots rampage with low consequences while homosexuals and sane bis watch in horror.

their community spokespeople are absolute weirdos

There are just so many of them.