What of it? Pedestrians traditionally have the right of way when interacting with motor vehicles, even if said pedestrians are stupid. How much of that rule applies when they are illegally blocking a street?
If my daughter can't run a lemonade stand without a permit, but people can illegally block traffic (no permit) without fear of any police intervention, we have a strange inversion of law. When you pick your targets based upon likelihood of compliance, you are part of the problem.
So what should happen in the absence of law enforcement doing its duty to allow traffic to flow freely? What should people who are trying to get to hospitals, or just trying to get home do? This "peaceful" act is not very peaceful at all. It tells law-abiding citizens that they essentially must come under the power of the mob. Free citizens, needing or wanting to travel, and perhaps not getting the Tweet saying what intersection a large group of idiots have blocked, are now stuck and at the mercy of a group that at minimum is taking their liberty to travel, and certainly may become violent.
This reminds me of John Locke's 2nd Treatise of Government, which is a classic that should be re-read periodically. Locke talks about altercations with others where the law is not ready to intervene as being part of a state of War with them, and specifically mentions the evil of impeding one's liberty:
He that in the state of Nature would take away the freedom that belongs to any one in that state must necessarily be supposed to have a design to take away everything else, that freedom being the foundation of all the rest; as he that in the state of society would take away the freedom belonging to those of that society or commonwealth must be supposed to design to take away from them everything else, and so be looked on as in a state of war.
18. This makes it lawful for a man to kill a thief who has not in the least hurt him, nor declared any design upon his life, any farther than by the use of force, so to get him in his power as to take away his money, or what he pleases, from him; because using force, where he has no right to get me into his power, let his pretence be what it will, I have no reason to suppose that he who would take away my liberty would not, when he had me in his power, take away everything else. And, therefore, it is lawful for me to treat him as one who has put himself into a state of war with me- i.e., kill him if I can; for to that hazard does he justly expose himself whoever introduces a state of war, and is aggressor in it.
He goes on to say, of course, that where there is not immediate peril, or where there is the ability to appeal to an agent of the law, one is not in a state of War, and citizens do not then have the natural rights inherent in such a state.
This of course is not perfectly analogous, and leaves us in an admittedly gray area. What do you call it when you are unable to move freely because of the willful and illegal actions of a mob, and there is no appeal to law enforcement to rectify the situation? In my opinion, it depends upon just how peaceful that crowd is. If one reasonably fears for his or her life due to escalating situation, it may well be necessary to leave that area at once, at any cost. I believe Locke would agree based upon his next paragraph (emphasis mine):
Thus, a thief whom I cannot harm, but by appeal to the law, for having stolen all that I am worth, I may kill when he sets on me to rob me but of my horse or coat, because the law, which was made for my preservation, where it cannot interpose to secure my life from present force, which if lost is capable of no reparation, permits me my own defence and the right of war, a liberty to kill the aggressor, because the aggressor allows not time to appeal to our common judge, nor the decision of the law, for remedy in a case where the mischief may be irreparable.When it comes to life and death decisions, the one who became the aggressor, who first moved to change the dynamic from civil society to a state of War, loses the benefit of the doubt, and loses the benefit of caution that the victim would normally employ in a non-dangerous situation.
I fear that we may see more of these incidents if this style of protest keeps up, and violence continues. The entire reason that it works is that the demonstrators rely on the restraint of the public. As simultaneous riots continue to give the public reason to fear for their safety, their restraint will be less of a given.