Just watched video of the shot...my observations:
1. The shot BARELY crosses the corner of the backboard - I'd say less than a 1/4 of the ball. It's being described as a "horse" shot, but from where he shot it, he has a pretty straight line between ball and hoop, IMO. Certainly in the spirit of the rule, this shot should count; but even by the letter of the rule, I don't think it's a clear violation.
Cal coach asked about the shot during a T.O. and was told it was too close to call. I agree 100%.
2. The centre official has a perfect look at this play - it's almost directly on his sightline. Certainly, if Shipp had been further behind the board, he would have waved it off.
My $0.02.