I don't know what 'violently protesting' means
I don't either. The thing is our mutual ignorance of the meaning of that bit of media speak isn't terribly relevant. The rioters have actually been charged with crimes; Felony Rioting, specifically. Here is the actual statute: https://beta.code.dccouncil.us/dc/council/code/sections/22-1322.html.
And perhaps the most relevant part of that is:
If in the course and as a result of a riot a person suffers serious bodily harm or there is property damage in excess of $5,000, every person who willfully incited or urged others to engage in the riot shall be punished by imprisonment for not more than 10 years or a fine of not more than the amount set forth in 22-3571.01, or both.
So any riotous trustafarian that texted any of their follows in a manner than that appears to incite or urge is a felon. Just yelling or holding a sign can get you there; all the prosecutor needs is some evidence. That's where all the phones come in.
Some folks got use to having their way with no push back under Obama. As these rioters and others (Dakota Access squatters, for instance) are learning, the worm has turned. The next Ferguson is going to be very different.