Hey guys, I talked to Josh last night and he gave me a bit more insight into why he chose Stanford:
He said he made the decision late the other night and that one factor that definitely came into play was the fact that it would be easier for his parents to watch him play in Palo Alto than it would be in Ann Arbor. He also said that for the majority of his commitment that he really felt like he was going to commit to Michigan but that in the end he felt more comfortable in Stanford. He continually has mentioned the Michigan fans and the support they showed throughout the process as well.
Also, it didn't sound like he had gotten an overly negative backlash from the Michigan fanbase, which is a good thing to report too. Overall, a good kid chose somebody else and while it would have been nice to see him in Ann Arbor, he'll do good things in Palo Alto as well.
EDIT: I don't post this to drag it on, or even to wish him luck. It's only to clarify why he made his decision and also to pat everyone on the back for being civil post-commitment.