It seems that you have more faith than I do that there is any sort of system in place to hold police accountable. I could be wrong. My opinion is influenced by some personal experience, some anecdotes from friends, and lots of horror stories in the media. What I've taken away from it is that cops are simply not to be fucked with, that they have virtually unlimited power, and that there is absolutely nothing you can do about it.

If there's no accountability, no checks in place to protect your rights, then you don't really have them. You're not standing up for anything. You're just picking fights with people far more powerful than you, which is dumb.