...square into the chest of the defender hard enough to knock him backwards a couple feet despite the fact that the defender is doing everything in his power to hold his ground, and then he does it a 2nd time and a 3rd time (which now has the defender standing under the basket), that is clearly a foul. I can see a ref allowing a little contact initially if both guys are battling evenly (no advantage). But when Waldow is able to move a defender back 6 ft (who's doing everything in his power to NOT be moved) he's gained a massive advantage.

Brandon Davies was good using his shoulder but he didn't do it over and over, like Waldow, until his defender was standing under the basket. The refs usually called him on it if he tried a 2nd or 3rd time. They just let Waldow get away with murder.