The cause isn't "stop police violence", it's stop systemic racism within the police forces of the USA. Police violence disproportionally affecting black people is a symptom of that systemic racism.
Disproportionately relative to what? Their share of the population, or their share of violent crime*?
*The usual trick is to claim police bias makes measuring violent crime impossible. But if one is not motivated to remain ignorant, there are a few ways to get bias-free statistics anyway. One is victim surveys, that don't involve the police at all. The other is using homicide as a gauge for other crime. Since it requires a dead body, and is mostly intra-racial, there's very little possibility or motivation to fudge these numbers.
It's amusing how you think that American cops need any crime, let alone violent crime, in order to to exact violence and death upon citizens. You must be white.
What does "need" have to do with it? The logic is more violent crime -> more police interactions -> more chances for an incident to occur. Outlier incidents do not disprove the broad statistics you had no issue in invoking before.
The cause isn't "stop police violence", it's stop systemic racism within the police forces of the USA. Police violence disproportionally affecting black people is a symptom of that systemic racism.