Stephen Jackson just went in on George Karl -- claiming the guy was straight "out of line" when he criticized Carmelo Anthony and Kenyon Martin for not having a father figure in their lives.
Then he fired this shot -- "George Karl's son probably wouldn't have made it to the NBA if he wasn't a coach. He would have never got the opportunity."
FYI, George Karl's son is Coby Karl -- who was undrafted out of college but played for a handful of NBA teams from 2007 to 2010.
"Kenyon and Carmelo carried two big burdens: all that money and no father to show them how to act like men.