Yes, those "left" beatings get zero widespread cultural support. Violence is not glorified by any prominent voices on the left.
Whereas racist and sexist voices on the right make a boatload of money and fill up the comments of every news article posted to Facebook. It's cultural.
This is just not true.[1] Even in our tech community it's pretty commonplace to see 'it's okay to punch a nazi' is a well supported position.[2]
[1] https://heatst.com/culture-wars/prominent-leftists-celebrate... [2] http://reason.com/blog/2017/02/15/now-its-okay-to-punch-nazi...
When someone thinks you don't deserve to live because of the color of your skin, you're well within your right to defend yourself against that idea. You shouldn't have to wait until they're knocking down your door.
Replace color of your skin with political belief, and you've just made an argument for Trump supporters who live in places like Berkeley or San Jose to violently defend themselves from liberal rioting.
For a liberal, its' easy to write off Glen Beck when he says Obama is a fascist for taking particular action. However, it is difficult to write off the Huffington Post, when they say Trump is a fascist for rolling back the previous administrations 'reform' (thus returning us to the hell-world of laws existing in 2007).
I suspect the right-leaning people in this thread would say the same thing in reverse.
I'll avoid naming them, but there at least 5 loud rightwingers who make millions of dollars promoting racism. Not just on the web, but on TV. On the radio.
This isn't a "people live in a bubble" thing. This is people exaggerating the size of the fringe left and equating it with actual mainstream right.