To some, it's a game, it's a challenge, and it comes with recognition and/or reward -- potentially in the way of private services or paid requests.
Or, as the quote goes, "some men just want to watch the world burn", whichever world they deem unworthy of existing.
Easiest way to think of it is as a competitive hobby. Groups compete to release stuff fastest for cred.
I get why someone would consume pirated content but why would someone take the risk of publishing pirated content? Is it the ad traffic that the publishers get?