The only possible reason for the suspension from MLB is that they believe the slide was illegal. In other words they had to view the slide different than the umpires.
Even if the call would have been made and a double play called ending the inning. I don't think there would have been a suspension. Is there any precedence for this suspension?
I can see how this was a tough call by the umpire. I can see how one could see it as within the rules or how you could see it being against the rules. Had Utley actually reached for the bag it would have been different IMO. But his slide was so late, he was actually past the bag before his hand could have reached the ground.
Anyway, no matter what the call, I don't understand the suspension at all. Whether legal slide or not, the intent is to break up the DP and win the game. When that happens there is always a chance that either the fielder or the runner or both are going to get hurt.
When we were young we were taught how to cleanly take out the MIF at 2B. We were not taught this rolling block technique.