Dude gives a good speech...

Probably the most gifted orator of the past 50 years... never mind that some of his points are rather specious, the man is just awesome at working a crowd. Notice, however, how he speaks to "My fellow Democrats", not "My fellow Americans". Yes he's at the Democratic convention, but he's on national (if not world-wide) TV, his audience is much broader than that.

Anyhow, others may have a different read on this, but it seems to me like he's going through the motions, saying what he needs to say about his party's nominee more out of obligation than out of conviction.