The chat is not the only way you can troll your team mates and cause them to rage quit (or scream at you and get banned themselves). I would actually say that the griefing created by people using slurs is actually pretty small.
You can be silent and ruin hundreds of games. Distinguishing that from genuinely bad players is not really easy.
You can be silent and ruin hundreds of games. Distinguishing that from genuinely bad players is not really easy.