If you're interested in challenging those beliefs further, I'd recommend a couple excellent books. Are Prisons Obsolete? by Angela Y. Davis Our Enemies in Blue: Police and Power in America by Kristian Williamspolice are an important part of keeping a society civil. Prisons (or some incarceration system) are needed for dangerous folks like serial killers.
I'll add it to the list! I mostly put that in because I do believe some kind of moderating authority is useful in society. Consequences for shitty actions are useful. People will take advantage of each other if there are benefits for be gained. And plain unmoral people exist too. Heck, I'm hoping to volunteer as a type of conflict resolution entity at Burning Man next week. So it's not like I reject the idea of cops in principle. But the way the system is set up now and the way it's trending is worrisome to me.