I think you guys miss a pretty critical point:
Although not all leftist are like this- MANY LEFTIST HATE YOU AND WANT YOU DEAD. YOUR EXISTENCE AND MORALS ARE REPULSIVE TO THEM.
It is a hard truth to realize, but some people do, genuinely, hate you without cause because their morals are so disgustingly twisted that they have no other choice. I would say it is a very small percentage of the left, but it is there. And it is magnitudes larger than the so-called 'white-supremacist' problem on the right.
It isn't stupidity, it is evil.