This is one of two things that I find upsetting about US the most. The fact that you don't call the police when you need it, and also(and more importantly) that a lot of people wouldn't call an ambulance unless they were literally dying. It's stupid, and I cannot even fathom not having friendly police or worrying about the bill for an ambulance.
The ambulance thing is a genuine risk in the US, but you're probably getting a very skewed view about American police.
The vast, vast majority of American police are friendly and helpful to the average citizen. I've called the police about all sorts of things and had professional interactions each time. I wouldn't hesitate to do it again if I needed to, and I live in a city with a reputation for iffy cops. In my personal experience, that's not how it's been.
Of course, I'm middle class and white. When I had long hair and drove an old car, my experiences were somewhat different, but not that bad even then. Enough, though, that I can imagine if I was a different race or economic class my experience would be different.
For most people it's that you are only familiar with what you grew up with. I was lucky enough(I guess) to grow up in a country where calling for an ambulance was a no-brainer, never ever seen a single medical bill for anything, and also where I've personally called the police about problems I've witnessed - all interactions with officers were polite and I wouldn't hesitate to call the police again. That's why it's so hard do understand for me that there are places like the US where it's not the case, and calling for an ambulance can put you in massive debt - it's just upside down when I think about it.
Not only can calling an ambulance put you in massive debt, which it does (not merely "can") in America, but interacting with the police is almost unanimously unpleasant in my personal experience. (Report a handgun discarded on the side of the road, get harassed because you don't carry photo ID every time you leave the house on foot, etc.)
