Okay, we know right away that "Every case involving a cop as the defendant, they always get let off", they get found get very often. The cops who beat Rodnety King went to Federal Prison. the cop Ramos who beat up Kelly got fired. So, we know that your statement is an exageration of fact.
BUT.......If we make believe that what you say is true, there could be a good reason for it. Rodney King was a POS criminal who fled from the cops in a high speed chase. When they caught him, he didn't cooperate, but he put a fight and got a whuuppin.
Do you REALLY think that those of us who obey the law, live decent lives and pays taxes care if the cops tune up a scum bag who flees from them?
The Thomas was guy was homeless schizophrenic who was nothing but a drain on society. Do you want crazy, dirty, dangerous schozos hanging around you? the people in my neighborhood don't, and that I why we pay for cops and prosecutors.
In a way, you are right. the cops probably got carried away in both of those cases. But you don't see the cops walking into the Sunday school and beating the Sunday school teacher, do you? The cops have never beaten me, or any of my friends and neighbors. Maybe it is because decent people obey the law and don't back talk or fight with the cops if we get stopped.