Referees police screens pretty woefully overall IMHO. Too often players setting the pick get away with pushing their hips out that little bit further because to ensure they make contact with the defender when, if they (and their ball carrier) did it right, there would be no need to move, or players get there that little bit late but no call. Just watch Redhage in action!
In this case, Demos ran through the screen? Fine, call it. But if Holmes deliberately grabbed at the leg, then that's a different situation. In real-time, Holmes would likely have done this whether or not Hogan had called a foul - there wouldn't have been enough time for Holmes to decide "Hey, Demos just got away with that", so he went for his own payback.