Earlier quoted context omitted.
> it would be illegal for me to use force myself (in modern countries, the state usually has the monopoly on use of force). No, it's not "illegal" to defend yourself in the USA. But get the name of a witness or you could end up in court for years. Many laws allow a defense, but you're responsible for meeting the burden of proof and legal fees. (The castle doctrine in some states was enacted to give property owners a…
The specific meaning of “the police don’t have to keep you safe” is that you cannot win a lawsuit against the police because you were the victim of a crime. Most communities hire police to do emergency response and would treat a failure of 911 the same way they treat a failure of water or sewer. San Francisco just values this less than other places.
For example if you say, "I think somebody is following me.", US police will just say, "So go file a restraining order."
They're not your friend, and won't let you use them as a tool in any way.
If you do call 911, the response time varies depending on the city and the nature of the call. In Detroit, you might get next-day service, if that.