This happened in 2009-2010 as well, from the Vanderboegh brickings to the random gun that fell on the floor of a Dem townhall. Some Tea Party blogger mistakenly posted the address of my old Dem congressman's brother (thinking it was the Congressman's) in 2010 and someone cut a gas line to their grill. According to this article, now my new Pub congressman is receiving death threats. Same old, same old.
Yeah, while left-wing violence is on the rise, it's mainly from angry rich white students (ie, Atlas poster types) and not from the town hall crowd. Town halls have always been nasty. I remember one girl was almost attacked for daring to ask a negative question of Allen West in 2011. The Allen West town halls got so bad (I went to all of them when he was my Congressman) that my mom tried to ban me from going, but they were usually held a mile away from me so a few times I'd just take my bike. Fun times.