They should be crated up, put on a slow, one-way boat back to the African motherland. Toss in a spear and a loin cloth for their “reparations”.
Africa doesn’t want them, but Australia seemed to work well for a criminal problem, so perhaps deportation somewhere, after a second arrest instead of filling up jails with 3 time losers. Like chopping off a hand for theft, it might be a big deterrant.