Biphobia in the bl community/series

I just realised how many times I've seen someone complain when one of the characters is bi because they are "bound to cheat", "unfaithful" etc. And he'll some authors feed into that narrative. I see bi leads/mcs in bl getting more hate than 'straight' characters who turn gay or who is only gay for the other character as an exception, and that trope is some orangutan shit. What do you guys think about this, or am I reading to much into things?