I'll admit, I haven't watched it repeatedly to check out his form or anything, but I imagine that it was a case of quite a bit of weight, a little over rotation, and him trying to save it at all costs.
If you have the distinct feeling that your arm is ripping in half, dump the weight. In all seriousness, I've only heard of a few cases of this happening.
I like (in a terribly sarcastic way) how this got so much attention. It's not like, there was actually an Olympic competition going on or anything that anyone would want to be interested in which might need some coverage.