https://en.wikipedia.org/wiki/Paradox_of_tolerance
In actual e-sports the main motivation behind self-policing is avoiding bad PR for the sponsors, so the human trash that had a heated gaming moment is coaxed to publish a boilerplate apology so that they may keep making money for the org. In this case you'll unfortunately have to rely on regular old human decency instead, which is not a powerful enough incentive for some it seems.
If you allow asswipes like this to be part of your community and do what they please in the name of propping up the numbers (or arguing some sort of ridiculous free speech defense, in which case see link above), your community deserves to die. Whether competitive TF2 blissfully fades into oblivion or has to be put down after contacting rabies is in your hands.