Eh, I don't know. Have you lived in a ghetto†? (Not a racial ghetto; I mean a
class ghetto—the part of a city usually referred to as "the projects.")
In a ghetto, "murder, muggings and drug crime" are [still] facts of life. In a ghetto, police cars are like beacons radiating "no crazies are gonna try to get in your face" as long as you stay within line-of-sight of one. Homeless people cluster near police stations in ghettos—for protection.
In a ghetto, someone's always passed out on a street corner, and the police are always there trying to see if they're just drunk or if they need to get to the hospital. Once or twice a night (more often on Fridays), you'll see a dude being forced into a cop car while a working girl stands there crying and bruised.
If you live in a ghetto, you've probably been mugged yourself. In fact, it's probably happened more than once. (3 times for me!) As well, you've probably been "threatened"—ended up surrounded by some "friendly" strangers, in situations that could very well have resulted in your death, if you did anything to provoke anyone. You've also probably had people follow you for blocks ranting and trying to grab at you. Or follow you, giving you a "guided tour" you didn't ask for, then insisting you pay them for their "tour" to get them to go away. And each time one of these things has happened, you've likely wished that there was a police officer nearby, but there wasn't; they were too busy dealing with all that other shit above.
If you live somewhere "nice", police officers can seem kind of pointless, and might in fact be a bit stir-crazy and awful. But if you live in a place where they're as over-worked as hospital ER staff with all the shit that goes on each day, you're usually somewhat thankful to have them there. Even if you still do feel intimidated and a bit scared every time you pass by one.
---
† To disclaim in advance: I don't mean one of those weird mid-US ghettos, with the police who grew up somewhere else, likely of a different race from the people who live there; the kind where all the awful racial police violence happens. I mean a ghetto patrolled by its own.