I have a friend who plays DotA 2 reguarly who alleges that toxicity is much less of a problem with that community because players can call out good or bad sportsmanship at the match end and this is taken into account by the matchmaking system. This results in all the trollers and flamers and griefers mostly getting matched up with each other in a mutually contstructed cesspit while the fun games happen elsewhere.

Does this match others' experience, or is it a bit of a rose-tinted glasses situation?