I wonder if Scribblehub could make a category for Bi protagonists instead of a sub-tag....
I don't mind if it's part of their backstory, past, etc... but I'm pretty sure I chose to read GL to avoid seeing the protagonist fucked by men, you know?
Futanari stuff is its own can of worms (and in my opinion a crutch for bad gl writers in most cases), but at least it's still Girls, in the Girls love tag, and not... a Man, in the Girls love tag, because being Bi is the workaround....