What laws are worth if they aren't protecting me? I might be unable to protect myself, right? A strong young man may have a physical force advantage over an old disabled woman, right? So the idea is that the police should enforce laws which say it's illegal to harm me, which we're calling "police protecting me"?
Law protects "order". That mostly means "protects the interests of the rich". Sure, avoiding rampant crime to the point that it's an obstruction to commerce is the cops job. Stopping the mugger/killer/rapist that's attacking you personally isn't.
If the cops have a choice of stopping 2 crimes or the crime happening to you, they're going to choose the 2 crimes. Presumably you and definitely I would choose to prevent the crimes happening to ourselves. Thus, self defense.
They are a paramilitary force lacking the civilian supreme command that, in the US, the actual military has, empowered by but not obligated to act to enforce the law, an independent and centralized power center.
https://en.wikipedia.org/wiki/Warren_v._District_of_Columbia