No doubt, it is not like the guy dominated pool for most of the 1980's with no skills. Sigel beating anyone is hard to call an upset.
As far as the jackass part, I think there is alot of act in that as well. Every sport needs it's bad guys to root against and Sigel is playing the roll to drum up interest IMO because he was never nearly as ignorant in the past as he is acting out now and when I met him in person he was actually pretty easy going and cool to talk to.
I mean think about it, he dropped his "Captain Hook" nickname that everyone knew and took up "Mike the Mouth" before the tour even began. It is clear he planned to come out on this tour and yap up a storm and become the guy people love to hate.