Just because cops might have too much power in the states and sometimes get armed with former military equipment doesn't mean you need to generally expect cops to act in bad faith the way you describe. It's not some "childish fantasy" that it's not like that in other countries, it's reality in may that police are generally courteous.
There was a similar discussion on here recently about it being a 'rookie mistake' to approach work situations in good faith and that you should have everything on contractual basis and getting a lawyer. That's such a horrible approach to live and again, from what I hear it seems to some degree be an unfortunate reality in the states, but that does not mean that it should be accepted like this and that it's just an inevitable part of a society.