I'm sorry, but that's ridiculous.
Talent is talent.
Playing defense isn't like being able to knock down three-pointers or something... if you have a certain amount of athletism (which OU does), then you should be able to play defense.
Are you really going to tell me that TMG or Gallon aren't athletic enough to play defense?
TMG is atheletic enough to blow past any point guard in the league when he's dribbling the ball, but yet he can't stay in front of them on the other end? And Gallon is athletic enough to average nearly a double-double as a freshman, but he's nearly stationary on the defensive end? Sorry... I don't buy that.
This is clearly all about effort. These guys have shown that they CAN play defense in stretches... they just don't have the desire to consistently play defense for 40 minutes on any given night.