Are you saying it is OK to have a steady stream of injustices from an undisciplined and unprofessional police force as long as there are no riots?
I don't see anything even remotely suggesting that in what he said.
His statement was a simple fact, bad things happen in the world on a regular basis because bad people exist, a few of those bad people are police officers, most are not. A few of the bad things involve the police, most do not. Acknowledging that something happens is not the same as saying that it's "ok" for bad things to happen. We should strive to minimize this sort of thing but it would be naive to suggest that it will ever be zero. It is fundamentally impossible to have a society in which there are no bad people. All we can do is continuously try to weed them out as they are caught.
I guess I got caught up in this sentence,
"The video showing police brutality was just the right spark at the right time. Many other gruesome videos have come and gone without more than a little grumbling in the press."What he called a "spark" was actually an outrageous act of injustice carried out against a defenseless person, by agents of the state. One reason people riot is because they have lost faith in justice being done in cases like this. We have seen in the past how bad cops got let off the hook - it isn't a slam dunk that police brutality results in a bad outcome for the cops.
The fact that other acts of great injustice could also cause have caused rioting is beside the point.
Injustice begets more injustice, and lays the foundations for the next riot.
I don't see any evidence that would suggest riots would happen anyway, without these kinds of incidents.
Thankfully, it also works the other way round - the situation will respond well to quick and efficient prosecutions, with fair outcomes.