In the US, it is the responsibility of copyright holders to protect their IP through tort litigation. Japan is so captured by industry that they will put people in prison for what should be a civil matter. I'm sure it's just a coincidence that it's mostly the IP of large corporations that is protected by criminal law. It's as if the police were to volunteer to be personal bodyguards for rich people. It's understandable, though: Japanese popular media is a core part of their "Cool Japan" soft power foreign policy strategy.