Not all jailbreakers jailbreak for piracy.This ^, plus they don't want people able to roll back the OS to a jailbreakable version where the person can install pirated apps.
I pay for my tweaks and apps and all my appstore apps. I jailbreak to customize my device the way I want, not to rip people off.
Agreed. I never pirate and wasn't implying jailbreakers do this, just was looking at it from the viewpoint of Apple who might take that sort of sweeping / false assumption approach as to why they fight jailbreaking so much (and don't allow OS downgrades).