Anonymizing photos of the violent ones is therefore likely to support their actions by making accountability less likely. To scrub ethically, limit it to the non-violent protestors. To support non-violence, better to help identify the violent people -- police or civilian -- the opposite of anonymizing them.
The thing is people are already being held accountable for their skin tone, and the likelihood of changing your behavior when you have lived your entire life in an environment of constant oppression for fear of being identified in a protest is marginal, specially during catharsis, otherwise you wouldn't see for instance people burning police cars in front of a camera.
Keep in mind also that many (most?) of these "violent protestors" are simply reacting against violent cops in a power trip. I can't say I wouldn't react violently against a cop intentionally running over me and others with its SUV, but I can say that I would be thankful if my face was anonymized no matter how I reacted.
Actually, a lot more whites are killed by cops than blacks. And before you say that's because there are more white people than black people, blacks represent only 13% of the population but commit 52% of the crime. So, you are less likely to get killed committing a crime as a black person than as a white person.
https://www.statista.com/statistics/585152/people-shot-to-de... https://www.channel4.com/news/factcheck/factcheck-black-amer...