What? No. Just no.

It may be different in the Netherlands, but in the US riding dirtbikes on public streets is illegal. The bikes themselves are not street legal. The bikes don't have plates, turn signals, mirrors or horns. They are not registered with the DMV. In Pennsylvania they are wildly in violation of noise laws for motorcycles (they drown out conversations indoors when they pass on the streets). Totally unlicensed and almost certainly therefore uninsured (which is again illegal). Riding bikes of any sort in gangs is further illegal, breaking all sorts of traffic laws.

This going after dirt-bike riders is not about going after a symptom or superficial attribute of some other crime. It is the crime. It is the actual problem.

If I were saying "go after cars with spinney wheels" (which are perfectly legal) or "go after people wearing only red or blue" (which is perfectly legal) then your comparison would be apt, but that is not what is going on here.