We libertarians, and especially we left-libertarians hold to one of two alternative positions.
1. There are only 2 categories: Sheep and wolves. Dogs haven't evolved yet. The notion of paying some Wolves to fight other wolves is all nice and good...but best case...they eat us slower.
2. There is only 1 category: Wolves. However there's been a lot of work put in to try to convince 90% of the wolves that they should give up their teeth and claws, and wear wool. We reject that shit.