agreed. the first thing I ever ask people that say that they're biloveual is what their preference is and if they've been with both guys and girls. Most either haven't been with both or have a preference, which is a dead giveaway. I'm sure there are some people that are legit bi, but for the most part I just think it's an edgy way people get attention because it's difficult to call the bluff.
If a dude says he's bi you're not gonna ask him to prove it. It's just annoying af though, because most people that say they're bi likely arent.