Remember to scream my name when I tear out your organs

There's a difference between a gratuitous line of dialogue that's meant to exhibit aspects of a character which only one player can hear - and an insult that everyone can see that's meant to disparage someone based on an unchangeable aspect of their person such as a disability.

There's a big difference between a fictional character that exists in the context of a fictional setting saying something and you, an actual human being communicating with other human beings that exist in the real world, saying something.

One is a line said by a fictional character directed at another fictional character while the other one is targetting a specific group of people who exist in real life.

Go to the bottom of the site and read the esrb bit.

If you don't want to let me simplify it. The game is rated T for what it can control. Online interactions are not rated.

Words or phrases meant to disparage certain groups are dealt with pretty harshly, and "autist" or the like falls into that category. There is no comparison of an insult that's meant to compare someone's intelligence with a group of individuals with learning disabilities with fictitious lines in a video game.