I don’t think we do.
If it wasn’t for the police, not only wouldn’t we be safe in our homes but also preys to predators. If police didn’t exist, groups and organizations of people will create their own government. Not exactly good, reasons in my eyes are not only would it lead to Anarchy, where people would basically go ballistic and needy for food, protection, supplies and etc. But the fact that people would form different gangs and territorial defenses. More lives would be lost than won. Resources would eventually become scarce, and no order would seize to exist.
Then who would scare bad people into behaving correctly? The most major factor that prevents total anarchy is law enforcement. Ever heard people mention how seeing cops make them nervous even f they did nothing wrong? Just the presence of police and knowledge that bad actions receive harsh punishment help keep people line for the sake of the safety of everyone else. Laws and the enforcement of them is needed for human society to stay as civil as possible.
We need valid authority, but what we don’t need is corrupt cops, and government that allow these horrible police to do whatever they want. There are good and genuinely steadfast cops that are here to help, but many do not hold those same values, and they ruin what being a police is supposed to be about.