No i disagree (maybe im bias lol) but i think Tommy did the right thing by not shaking hands at the net.
Its weird but in tennis to me, thats like the definitive way of showing your opponent that you have no respect for him/her, and why should Tommy show any respect to Fabio? He acted completly inappropriatly and insulted Tommy...it would have been completly hollow and pointless for them to shake hands.
It is like when Feli Lopez refused to shake Paes' hand after his doubles match...he had a problem with Paes so why go out of his way to be "nice" (for want of a better word) to someone you dont not respect?
But then that is just my opinion on the whole thing..