I think you're conflating issues with the institution of policing within the United States with the behavior of individual police officers. Without getting into the politics or philosophy of the comportment or purpose of a police force, there are some things in situations like this that are fact:

1. Police officers (and more importantly, prosecutors) are incentivized to make arrests and have those arrests stick.

2. It's a well understood psychological phenomenon that individuals are much more lenient of their own actions. They call this attribution theory in psychology [1].

3. While policing is a risky job, it comes with privileged treatment, powers, and trust that a common citizen does not have. As such, and as public servants, we hold those with these powers to a higher degree of responsibility and behavior than those without such powers. To hold police accountable, we need a minimum level of oversight and control. Historically, this has either not happened or been circumvented by way of police unions establishing ill-advised contracts with the local governments they work with. [2]

I'll agree on points that individual police officers aren't evil, but I'd need a lot of convincing to believe that many policing organizations within the United States are not being held accountable to an acceptable level; nor are they being trained in ways that encourage appropriate interactions with the public they serve.

[1]: https://en.wikipedia.org/wiki/Attribution_(psychology)

[2]: https://chicagounbound.uchicago.edu/cgi/viewcontent.cgi?arti...