Wait, why do we think it is hypocritical, in terms of the police, to be driving badly etc etc? From your son’s pov (and yours from what you mentioned previously) the police are the hypocrites so he is only doing what they do.
It sounds like a Robin Hood complex. a god complex might be adjacent but unless you think he’s a narcissist or a psychopath/sociopath, it seems unlikely.
with adhd you spend your life being judged and told off by people who don’t have the right to do so. Horrid teachers who don’t make any effort to understand you. Other kids who call you weird for no apparent reason. Your parents. Other people who say you talk strange or too fast or too much. The police… who do hideous things like WhatsApp each other about wanting to rape women they’ve arrested, or take photos with dead victims, or kidnap young women off the street, or treat victims of domestic abuse with disdain. (You yourself op say your dealings with the police have been negative). So why should/would he, in his mind, need to respect the police? Or care what they think? He doesn’t care because he probably was in trouble a lot growing up (however small it might seem to others, clearly it was an injustice to him). And he’s now hyper vigilant to and affected by injustice. And he’s looking for a way to clear that rage from his system so he doesn’t care if he gets caught.
not to mention the stupidity being pushed by YouTubers. He’s got far more to gain from being arrested for his Robin Hood work — emotionally, psychologically, financially and reputation-ally — than he does from putting his head down and doing his job.
he’s not dim. He’s looking for a way to do something meaningful (to him) with his life because he got sick of seeing injustice. He’s an empath. But he doesn’t realise that he’s hurting the people he loves with the way he is going about it. And is probably friends with some dickheads. And is young.
all most people here are suggesting is that hems being a dickhead because he’s “hurting” arseholes. So why is he going to stop his behaviour and listen to you or the police doing the same? The shopkeeper about to take some incapacitated old man’s money - arsehole. The people he’s pulled over - arseholes. The people picking on kids - arseholes. So saying “oh you’re being an arsehole because you probably drive badly and aren’t in a position to reprimand them and the police won’t be happy” does nothing. As far as he’s concerned, he knows he cares, he knows these people don’t care, so why is he the one still getting told he’s in the wrong?
anyway, if you can find a way to have him demonstrate this positive trait in a healthy way, you might be able to stop it but just telling him he’s wrong is going to confuse him - because he’s not wrong at the core of it, and he can’t see past that. He’s Robin Hood.
and yes help him understand he is going about it wrong but not because it might upset the police - but because things like…it demonstrates to nasty people watching YouTube videos like his that they can pull people over and fuck with them, but they’ll just do it for fun not for a “positive” reason.