You have left out of your question the obvious defect in people coming to such strong and fixed opinions on the matter, that no official investigation has been carried out to reach a conclusion; nor in a land of liberty where by law people are assumed to be innocent until proven guilty, there has been a swift rush to judgment in public opinion, not even based on full knowledge of the events in question let alone the motives of the participants. There is more to the story yet to be circulated widely in the media. All such events that are embraced immediately by the public are first of all a consequence of carefully laid groundwork. There is mind control manipulation going on relentlessly all day and all night via the electronic signaling involved with telecommunications, including cell phones being used, radio and television broadcasts, and the Internet, with WiFi signals being picked up by human beings who may even be asleep, because there are frequencies transduced by nanoelectronics they have ingested as contaminants in food and beverages, including bottled water, disseminated widely throughout commercial sources—no one escapes this.
It is then a question of vulnerability and the particular leanings. The propaganda messages interweave narratives that will trigger people regardless of their political leanings. Those on the left will become incensed at the apparent police brutality of this particular incident and sympathize with the downtrodden black community seemingly preyed upon relentlessly by white people in power or their minions, the police officers assumed to be corrupted heavily by racist beliefs. Those on the right in their thinking are more inclined to be sympathetic to the problem of law enforcement dealing with so many out of control individuals, difficult circumstances, and increasing public pressure assuming the worst about them, and having a thankless job. They are inclined to be more understanding that some people will break under the strain and perhaps go to extremes, but even when assuming the worst about the police officers in such an incident will not be sympathetic to the idea of protesting every police department everywhere—that is what is so unusual in these circumstances.
People vary greatly in their personal beliefs, their level of sensitivity, and the likelihood they will become motivated to take part in a protest of some kind, even risking personal safety to do so. Normally, it would take an extreme circumstance where there is a very significant personal threat or something affecting their loved ones for people to become so involved. Even under those circumstances, demonstrations are a very inefficient means of righting wrongs. They are self‑satisfying to the protestors who need to expend the energy of their emotions on what they perceive to be a just cause, but their ability to persuade the powers that be and the institutions they may be railing against are relatively meager given the state of political gridlock and the power of vested interests who are rarely in favor of helping the downtrodden as a high priority.
There are many perspectives always in a given situation. Much will not be observable on the surface, as in addition to the facts of the case, so to speak, there will be deep cultural influences and imperatives that motivate the participants in varying ways because of personal history, in addition to the cultural environment and its effects on behavior through conditioning. Given the reality of ongoing manipulation of the population as a whole to create divisions, points of friction to degrade happiness and stimulate discord, conflict, and even violent actions on the part of those who are inclined by temperament and past history to be reckless or even self‑serving, given the size of the population, you can see by the numbers generated among the protesters and the additional individuals involved with actual rioting and looting with acts of vandalism and violence against fellow participants, it is a quite dangerous situation that has been created and unleashed. It is wholly unnatural and is simply the opportunistic manipulation of a tragic event that was orchestrated to happen to begin with, through similar manipulation of those involved directly and to extrapolate that onto the general public to take sides, to be ramped up in extreme agitation, anger, or fear, as the case may be, and to call people up to bring them out from their homes onto the streets, and with ramped-up emotions become more prone to putting themselves and others in danger.
None of this truly serves the assigned goal to awaken hearts and minds to the perceived systemic racism, demand action from the powers that be, and cause a kind of social revolution to create a better and fairer world. Violence begets violence—that is the legacy of these demonstrations. They are both a cover for and an evil twin of the rioters. The protesters are serving the darkness every bit as much as the rioters because protesting in an exaggerated interpretation and display of anger and displeasure at a huge group of individuals who wear a police uniform but are not guilty of any crime whatsoever, will not serve race relations or living in harmony and cooperation with the authorities.