There is no free speech right to "cry fire in a crowded theater". Every right enumerated in the Constitution has a limit. There are cases where other principles and rights win over the First Amendment. There are endless cases about religious rights and other rights, for example.
And when there are those who want to murder me because I'm a Democrat and attack me for my Jewish background, they should expect pushback and not start whining like spoiled brats when it happens.
Great post. The limits of free speech are really complex. (BTW, the "crying fire" example is often used, but it's not a good example.)
As I've studied free speech the phrase that comes up repeatedly is "imminent violence". As I looked at videos from the weekend, I believe the alt-right asshats were careful to not cross that line. So vile as their messages were, I believe they were protected speech.