Obviously the violence (breaking a window) is wrong and is not protected by free speech.

And perhaps they should have gotten a permit to march. I don't know the rules in St. Louis. But the act of protesting itself is protected by the First Amendment.

So is Flag Burning. I don't like flag burning personally and would never do it. But it is someone's free speech right. By critiquing flag burning you are directly critiquing free speech.

Free speech is under attack right now and I agree with you that we need to stand up and point out when people are attacking the free speech rights of others. But you went the opposite direction with this thread.