Being an attention whore is a completely different thing from being trans. That being said, quite a few trans people do get like that, but many still don't make a big fuss over it. Tbh, I've never actually met a trans person who was like this, I've only heard about it. I think it's more of a confirmation bias than anything, since the ones who aren't noticed in a negative way typically aren't noticed as much at all. They become most of what people pay attention to, and thus a stereotype is born.