I don't think that the Predator will be out there stopping crime and walking old grannies out there on the streets, rather it will simply handle things worse than it. I look at Scarface's story as reference. While he would normally be an antagonist to humans, him taking down Borgia Industries was a net benefit good to the corrupt city of Neonopils, despite his goal being a mostly self-driven goal. Keeping crime artificially high, black arms deals based on alien tech sold to war torn countries, crimes against humanity in their experiments, ect. Morally grey vs grey-dark or black is the perfect spectrum.