As for how a civilian PD differs from what the NYPD has become, let's start with not using tactics and weapons against peaceful, unarmed citizens that are only suitable for a war zone. The people are not Al Queda.
And let's stop arresting and jailing Journalists, let's stop beating up minorities, unlawfully targeting and harassing them, among other things.
And do not fudge crime figures to make it look like you are actually fighting crime, when apparently you are not.
Do not 'fix' tickets to benefit your buddies and family, treat all citizens equally, according to the law.
But using military weapons and tactics on US citizens peacefully exercising their rights distinguishes a civilian Police force from a militarized one.
We do not want the military patrolling our streets, it is unconstitutional and for good reason nor do we want PDs armed and trained as though they were going off to war, instead of enforcing civilian laws right here at home.
Sure, it's a dangerous job, but far less so than many other jobs. And no one is forced to be a cop. If they feel that threatened, find another job. Some cops seem able to do a good job, so it's not impossible. And the more they alienate those they are supposed to protect, the more dangerous they are making things for everyone.