The violence is deplorable, and most of the protestors really suck.
That said, when was the last time we saw this w/ a major candidate for POTUS? At some point, I don't think it's out of line at all to take a look at the candidate & the campaign, and say "hey...maybe there's a connection here."
Trump is divisive and thrives on being inflammatory. He sees America as separate, disparate groups - Mexicans, Muslims, Christians, women, losers, winners...whatever it is. Instead of focusing on what we have in common and what brings us together, he highlights the differences and blames them for our ills. It's all us against them for him, and if you're them, look out.
His supporters justify this by saying he's "not pc," but that is a complete perversion of what the term "politically correct" means and how it's applied. Trump isn't "not pc." He's a divisive demagogue, who just likes to insult people & create division.