[almostjazz]

That is only part of the equation. You may be removing more malevolent actors in the immediate short term, but depending on how that policing is done, you might also be creating more malevolent actors too. Overpolicing a group can create distrust between the community and the police. Once you feel the system does not care about you or treats you unfairly, there is little reason for why you should care about it. And if P(Caught|Group X) != P(Caught), the system is treating you unfairly.

I would argue we as society don't want crime to stop simply for the sake of crime stopping (or for prison labor), but ultimately because we want to feel happy and safe from harm and unjust treatment. The systems we design need to factor in the humanness of the police and their communities and make sure they are not set up in a way that loses sight of that bigger picture.