Hate speech that calls for violence can incite violence, the irony is that we see this mostly coming from groups embraced by the left - 'death to Jews' is preached openly by many Muslims but seems to be perfectly acceptable to the left and Obama's association with such people was covered up by the media (so they know it's wrong and unacceptable).
Does anyone here think that (as has happened in the UK) that gangs of (often) young disaffected non working young men in their late teens can stand outside the homes of and shout and laugh at disabled people or downs syndrome people without the government using its power to intervene?
This is clearly a public order offence and targeted harassment of individuals so the police could and damn well should intervene and no-one's free speech rights will have been violated if they do. But if someone was arrested for trying to argue that downs-syndrome in general should be screened for, aborted etc... then that would be a violation of free-speech - that is where the argument needs to be made by people with the opposing viewpoint.
I think the problem also is in describing views as "left and right". Some of my views chime with the traditional right (no where near extreme), some with the traditional left (no where near the extreme) and most are probably in the middle.
That is really the majority of people who are not near either extreme. Right now though, according to many, that makes you an extreme alt-right nazi because you are refusing to completely embrace the extremist of the left and their thinking on everything is completely black and white. This thinking and labeling of everyone who doesn't buy into the extremism of the left is what got Trump elected - if you start calling normal people "racist" (many of who voted for Obama) then you devalue the term and make it meaningless.
Nowadays, according to the left, everyone (except them) is racist, sexist and homophobic - even the likes of Dave Rubin who's gay married. Don't want to date a man in a dress? OMG, you're transphobic!
Of course when Trump won in no small part due to the behavior of the left, the left double-down on the labelling and call everyone misogynists. I think Clinton has since blamed everyone else and used every reason for her loss - apart from the obvious "I was crap".