I think most cops are decent people trying to do their best, but the notion that the job doesn't also attract power hungry dadholes is naive at best. There is not a preponderance of cops who are racist, but there are more than there should be. There is not a preponderance of cops who think their badge and gun give them the right to treat citizens (of all races) like crap, but there are more than there should be. There is not a preponderance of cops who shoot first and worry about the consequences (in the rare instance that there are any) later, but there are more than there should be.
The way I look at it: If you are a racist who is pre-disposed to violence, there are a very select few occupations that are open to you where you can get paid to be a violent racist. Does that mean all violent racists become cops? Or that
only violent racists become cops? Of course not. But it does mean there is an over-representation of that sub-group in the police world than in the larger population. And a big part of why that 'police earning the hate' thread gets traction is because there is a knee-jerk reaction by the Thin Blue Line to rally around the bad apples; I wonder how many of the body cam videos shared in that thread straight up do not match the accounts of the incident in the paperwork. If you are a good apple who remains silent in the face of a bad apple, you are also a bad apple. My FIL tells stories of how he ultimately got out of police work shortly after his sheriff department stood up a SWAT team. As county sheriff, the team was under his command, and as a military combat vet he approached it with that sort of disciplined mindest. But to his not insubstantial alarm, he found that nearly all the other guys who applied to the team were absolute yahoos who looked at training as an excuse to do 'cop rolls' out of moving vehicles. And remember, as a SWAT team these guys were establish LEOs.
And it can also be a chicken-egg thing. You may go in as a do-gooder, and after a time of seeing nothing but minorities at their absolute worst (cops aren't typically called to respond to something good happening), that tends to shade how you see that world.