I would not endorse participation in a mass protest because it is pointless. As a political act, it communicates the fact that the government is not literally in control of each person, which is comforting to some people who are compliant and unhappy, while it is terrifying to some people who are compliant and happy.
Now, the political effect of every mass protest is to impel government action to either appease the crowd or to destroy the crowd, because the crowd is irrational. Appeasing the crowd may be dehumanizing and destroying the crowd may be inhumane, but both of these are normal functions of government (appeasing a group of people under its jurisdiction or destroying a group of people under its jurisdiction). The only thing special about mass protest is that it is a public spectacle. It allows leaders to justify their actions, to pretend that they are not responsible for what they do, since “the people demanded it” or “the people were out of control.”
Either way, the leaders do whatever they want, and the people in the crowd are not treated as individual persons, but more like animals. Groups of animals may be fed, sheltered, and comforted, or they may be confined, exploited, and killed. No one asks them for a political position statement.
Mass protest against police violence doesn’t really solve the problem of police violence. It just pushes the government to either appease the crowd or to use police violence to make the crowd shut up. Either feeds the paranoia of the individuals in power. The more they treat people as crowds, the more the people in crowds act like crowds, which makes the people in power more paranoid.
Is a crowd “wrong” because it is made up of poor, ignorant, sick, lawless, or ill-bred people? No, the type of people in a crowd does not make it necessarily wrong. From the point of view of someone who believes himself to be above a crowd of different-looking people, exercising authority over a crowd of lesser people, or protected from a crowd of unruly people, it may seem like the main problem with crowds is that it takes so much pepper spray and riot gear to clean them out of public parks and streets.
The crowd is wrong because joining a crowd means giving up personal responsibility. Even if a crowd were motivated by good feelings and accomplishing good purposes, it would still be wrong. It would still be a group of people who don’t want to act like persons because as persons they don’t feel powerful enough.
But even if a crowd of self-righteous, highly educated, wealthy, law-following, taxpaying, property-owning people all decide to be upstanding individualistic heroes, they are still a crowd. They still follow stochastic patterns of group behavior; they still appropriate stupid ideas as dogmatic ideology; they still respond instinctively with paranoia when their tribal symbolism is desecrated; they still savage anyone who deviates from unspoken norms; they still immerse themselves in thoughtless, indifferent violence; they still lie, cheat, and steal under cover of anonymity. Their crowd doesn’t have to gather on the street, in the open, because they own the street.
There is no justice in crowds. The crowd seeks a palliative, a sedative or a release, not justice. “Mob justice,” like “crowd control,” is final because it can never be questioned or evaluated; it can never be justified because it has no principle of reason.