I mean, I didn't give Polish police as a random example without ever being to Poland you know. I'm Polish and based on my several interactions with the police I wouldn't hesitate at all. I would definitely describe them as friends and they do generally want to help.
I read it as a rebuke to a generalized statement that you characterized as US-centric, hence implying that outside of the US the police are your friends. You also said "they do generally want to help" which is a rather explicit generalization.
If you just meant to say that the police are your personal friends, that's fine I guess, but the comment you replied to didn't really rule that out in the first place.