That doesn't negate the possibility that GZ did strike or do anything else to his GF. He took the anger management classes to have the charges dropped. He PAID for those classes. It's a common plea agreement the Prosecutor will offer for a 1st time offense where major physical trauma has not occurred.
Been there, done that, neighbor who jumped my fence and was creeping around my property was confronted by me AFTER he jumped back over to his side, he threatened to shove my Mag Lite up my a$$ and then went on to threaten neighbors who had come to my aid. He was charged, made a plea agreement with the Pro, w/o my knowledge, and went to anger management. It does NOT mean he did not threaten me or my neighbors. Or that he was intoxicated, had his sidearm, and was trespassing.
He later went on to assault my BF several years later, and racked up other charges with other neighbors.......IMO, it sets up a pattern.
Reduction of charge, or dropped for diversion program does NOT mean GZ didn't commit the crime initially charged.