He was convicted, but could've been that he took a plea deal because he didnt want to take the risk of losing at trial(which could've cost him years behind bars). This doesn't mean he actually commited the crime he was accused of, he just didn't want to risk his life, fighting this charge (bc he knew he would likely lose at trial). He probably figured he'd pay restitution etc. and move on with his life. Unlucky for him, he hit big and now they want everything he won.
I don't disagree at all...if that was part of the plea he took, then so be it. He has to pay back what he owes