Okay, I've been reading several topics on Reddit about it lately. It just blows my mind that people actually think that it's just the kind of community and we kinda just have to roll with it, like muting people, etc. What is happening in this game is fully Valve's fault, let me explain.
To put it straight, it's all happening because Valve allows it. The solution is very simple – bans. If a person insults somebody during the game, he gets banned. Maybe few warnings and/or temporal bans at first, second chance is a thing after all, but if somebody consistently being an asshole (3 games per month at best), he should not be wanted in this game anymore. This is not a community fault, if you allow something, people will do it and even chill dudes will be influenced at some point, especially kids, who are the major playerbase in the game.
In reality Valve don't care. I'm not sure what's the reason, but if it's the most common Reddit's assumption – being afraid to ban all toxics and end up with smaller amount of players – than Valve not only guilty of allowing toxic behaviour, they are double guilty of allowing it totally on purpose.
You know how I know that Valve are okay with it? I know that I can log in and type racist, sexist, hateful things about dead parents, horrible death wishes and other fucked up shit and I will be totally fine. At best I will be muted. Wow. And I'm not the only one who fully aware of it. Public media faces, world known players, winners of TI also know that they are fully safe, they are even safer cuz they can't be reported or something, don't know the details. Just think about it. A winner of the biggest eSports event can publicly express his regards that Hitler did not made a genocide of some other nation and than make fucking twitter apologies and get away with it. In most other games, video or not, such behaviour will definitely be the instant end of their career, probably a sue for a pretty big amount of money. Valve, however, are totally okay if you just open twitter and type your appologies.
So no, it's not the community. The community is indeed horrible, but that's the cause, not the reason. It's totally up to Valve if we can play in this game and enjoy it or continue to exist in this toxic swamp.