There is honor among thieves. They don't want to believe they're the worst kind of people in the world (and they're not) so they look down on someone else (someone who deserves it). It's not a bad thing, though it might sound that way the way I describe it (we've been trained by politically correct psychology types that looking down on anyone is a bad thing). The foundation of morality is based in part on the idea that some acts are worse than others.
There is a definite pecking order in prison. Cop killers are at the top and chesters are at the very bottom. Peterson will be just above the chesters. As an LEO, I can assure you that chesters have a very miserable life in prison. Peterson will have a very rough time, too. If he ever makes it to open pop, he'll be turned out real fast. For those unfamiliar with prison lingo, getting turned out means you're going to be Bubba's wife and you will be performing your marital obligations.