Cops earn too much money to be proles. They are petty bourgeois who use their $120000+ annual salary on paper and the guarantees of a lifelong pension to invest. In a way, I don't even think calling them "foot soldiers of capital" conveys this well. They're more like armed members of the petty bourgeoisie sanctioned by the state looking after their own petty bourgeois self-interest alongside the class interest of their bourgeois masters. The armed members of the petty bourgeoisie not sanctioned by the state are fascist paramilitaries, and surprise surprise, there tends to be cross-pollination between the two because the class background of the two are identical. When a pig evicts and beats the shit out of a tenant, they do so so that their tenants would know their place.