Why are American players so racist in Dota and why is Valve not doing more about this?

The last few games have been a horrendous experience where players have made fun of peoples accents (especially if they are Indian) used the N word and said things that honestly should not be repeated anywhere. The community also brushes this off as report and move on. I get that but it affects people a lot. A few games ago some dudes accent was made fun of and he just said "this is why I never use comms" and abandoned the game. It got to him and it affected his confidence.

This is not right and it is down right disgusting. Please speak up more on this and let Valve know that this is not right.

Edit: I can tell by the downvotes and replies that many of you have not experienced racism or know what it feels like. Your responses are equally damaging. You should know that. In the end its just boiling down to "dont speak bro" use chat wheels and pings. Just dont speak cause the racists will get you or just mute and move on. All are insanely bad options.