[[Lavender Brown is so underrated, it makes me sad. She’s amazingly brave and dies heroically and she gets the reputation as the boy-crazy skank because of the whole Ron thing.]]
She gets that reputation because that’s how Rowling wrote her. Even before Ron she was written as a silly, frivolous girl who cared about make-up and boys and divination. Harry didn’t understand her and Hermione was the epitome of “not one of those girls” in her contempt for her.
Fleur received much the same treatment, we were meant to ignore her sacrificing her safety to help with a foreign war or her being the most qualified student at Beauxbatons and instead focus on her accent and beauty and femininity and decide that she was a stuck up bitch. Not like Hermione who didn’t care about her appearance and preferred books to boys. Not like Ginny who made out with boys, but would rather play Quidditch than gossip about them. Those were girls we should respect. Feminine girls were vapid and worthless.