4 points
If the smurf detection/etc is good, then that’s the first way to alleviate those toxic behavior. It’s a really bad feedback cycle when smurfs are involved. My main game is rocket league, you can have smurf that win the game single-handedly and then start to play 1v3 or 2v4 because he decides that he wants to lose these games to keep playing at lower rank, or something you did the smurf don’t like, and you might be some MMR away for your next promotion and it doesn’t matter. The MMR matchmaking this little shit to your matches because he decides to smurf instead of playing at his normal level.
I don’t know much about dota or moba games, but the idea is the same, smurf will pump more negativity into the game.