Obviously Luke is a kind of martyr, and I think the police represent "normal society" in general? That makes sense to me, but there are probably some other good interpretations.
i just took it as a good-old general anti-authority fuck you i won't do what you tell me feel for now but on the 'normal society' part, in the scene where Luke is talking to his mother, doesn't she say something like "why couldn't you be normal/have a normal life?" or something along those lines?