Sam and Dean Winchester are too innocent lads who get mixed in with the wrong people and get framed for a bank robbery for not doing what "needed to be done."
Castiel and Gabriel Novak have a bad name, the didn't mix in with the bad lot, they were the bad lot. They are the worst men in prison- everyone is scared of them but wants everyone wants to fuck them.
That was how things went around here, fuck or be fucked. Meaning either have fuck someone or have them fuck you. It wasn't always like this in Gallifrey prison, it used to just be a normal prison until the Novaks arrived. Then the Winchesters arrived. inmates and officers alike very much found the two brothers extremely attractive- however they don't know who they are dealing with. They are dealing with the Winchester brothers, and no one messes with the Winchester brothers. Except maybe the Collins brothers.