Why does the creepy guy in manhwa/manga always have to be ugly

I'm sick of this, whenever the author has to make the leads get closer, they introduce the infamous most original scene, the poor fl/bottom (this works for both bl and straight comics lmao hilarious) is harrassed and followed by some creep who is always drawn ugly or fat or both, and the knight in the shining armour, our ml, saves the day by banishing that beastly abomination. Honestly it's so overdone but can we not portray ugly people as bad people too. It's like authors entire artstyle changes when when they're trying to draw this specific character. Whenever they introduce any character that shows criminal behaviour, especially sexual assault, they are always drawn ugly, kind of pushing the idea that if a super hot guy were to act creepy, the women would love it.