Bro....

YTA, big time.

Dark humor is when you make light of a serious but relatable event.

Me making fun of myself using an ouija board to contact a dead relative is dark humor. Someone talking about how saying "my bad" at a funeral is not a good look is dark humor.

Y'all were straight bullying this girl because she probably gets similar comments from strangers about the scar, and probably feels bad about it. When someone says "please don't joke about this--" that's it. You don't get to excuse it, you don't get to talk about "oh, it's just how they are."

Y'all may think it's funny but it still hurt her feelings. She said it hurt her feelings and you ignored that. You do not control how other people feel about things, and for that, you're a HUGE AH.