zlacker

One answer is law enforcement is largely a bureaucracy of career civil servants, so they're not as subject to the whims of a mayor or elected officials.

On top of that they're a fairly politically active group, so they have an outsized influence on policies, including those that affect them.

But the biggest issue, as you note, is the sheer disparity in who interacts with the police at all.

From a 2015 Bureau of Justic Statistics report

https://www.bjs.gov/content/pub/pdf/cpp15.pdf

Only about 10% of Americans had police-initiated, non-traffic stop contacts.

So 9 out of 10 Americans never see the police, much less have insight as to whether they're too violent.

Blacks 50% more likely than Whites to be subjected to a street stop by police.

Blacks 120% (!) more likely than Whites to be subjected to police force.

And, every single respondent who indicated they were Tasered by police felt it was "excessive" force.

So, yes, fundamentally this is a "rights of the minority" problem - and the minority in this case are younger, poorer, less politically connected, and therefore are underrepresented in discussions about police brutality, effective law enforcement, police training, and other policies which impact them.