Honestly curious, why do people get so upset over insults towards them in game?

I'll put this out there first, I'm not toxic in game, but if Riot was more lenient with toxicity punishments, I'd probably be more toxic towards people who intentionally ruin games.

Moving on, why are people so offended by things said in game? Who cares if some asshat in a game calls you a bitch or tells you to kill yourself? He's just some angry kid in his room? If they're just toxic, they're not ruining the game. The people who intentionally feed are the ones people should be upset over.

I've actually been in a game where there was a guy feeding, he was flaming everyone, and someone on our team said, completely seriously, "You're giving me PTSD."

Fucking PTSD. (The guy was a dick and should be punished, but still) Do people actually get so offended that they think it relates to actual PTSD, like when you watch your friends get shot?

I don't know, can someone help me understand?