It was forceable contact above the shoulder with the crown of the helmet, whether he was defenseless or not is irrelevant. That hit violated 9-1-3 and 9-1-4. The defenseless player element only comes into play when not using the crown of the helmet; i.e. a shoulder to the head of a wide receiver catching a ball on a slant. You can make a pretty compelling argument that Elijah Lee violated 2-27-14 more than once against Baylor.
That crew we had on Saturday was really bad. I thought so while at the game and that was confirmed when I watched on television later. That 15 yard sideline violation they called against KU was one of the five worst calls I've seen this year.