It's called the blue line of silence, it's basically the law enforcement code of omerta.

I'm not sure if he supports the Mafia Cops, I doubt it since they're not feds and they were basically thrown to the wolves and condemned by everybody.

As for the bounty, I'm pretty sure if an up and comer had Pistone whacked he'd get it, by it, I mean a .38 at the back of the head.