That's because McCain and Romney are political oreos: Democrats look at them and say, "that what a Republican should be," because they know they'd cave to practically everything. Just look at the so-called obstructionist Congress of the past six years: virtually all budgets under Obama were passed with only the occasional amendment or rider that had benefited them. There were a lot of show-votes and Congressional hearings, but not actually a lot of obstruction against the most socialist president in recent history. And Congress was designed to be constantly gridlocked.
Anyway, I'm all for protest when there's a point or something that can be done. This is just an expression of displeasure, and while that's fine by itself I personally don't give a shit about someone's political feelings...particularly when it involves blocking traffic, looting, and allegations of astroturfing. I don't see any of it adding anything to the table except recalcitrance on both sides.