Every competitive game has an issue with a large part of their player-base being toxic. This may be the old and jaded part of my mind talking here, but I don't think there is much that can be done about it.
The underlying issue is that young men in their teens and early twenties have an existential need to express their adulthood and alpha-male supremacy (Not a judgement, as I was a little fucker when I was young myself... just speaking from experience), When you put a bunch of these young males together in a competitive environment mixed with a modicum of anonymity, or at the very least, a buffer that assumes that your actions/words won't end in physical confrontation, you end up with the sort of trouble that this thread is bringing up.
What can you do? Not much, aside from understand why it's happening and ignore it the best you can.