Former House Speaker Dennis Hastert sexually abused minors while he was a high school wrestling coach. He wasn't punished for that; the statute of limitations had passed. Instead, he was imprisoned for withdrawing his own money from his own bank account.
Football player Greg Hardy got away with domestic abuse. But he's not a popular figure and is out of the NFL. I wonder if he'll get the maximum punishment for cocaine possession as "payback."
Hastert's a bad guy, but there's no justification for the law which he violated. Hardy's also a bad guy, but he doesn't deserve any punishment for possessing a substance.
Just because both hurt people, doesn't mean they should be punished for actions that hurt nobody.