After the Giffords shooting the left rushed to blame the right's "hate speech" for inspiring it. At the same time then sprained their collective arms patting themselves on the back for their own tolerance. Of course it was all a crock. Just a few weeks before the shooting President Obama set the tone by calling Congressional Republicans "hostage-takers". Now that they lost the debt ceiling show-down, the left, starting with Vice President Biden, has taken to calling the Tea Party "terrorists". Do these guys even listen to themselves? But, why are they so angry? Why are they using such hostile terms? There are three factors.
Many of them are simply venting. They are angry. Not only did their man, Obama, fold again, but this was supposed to be a big win for them. The plan was to force the Republicans to pass some sort of tax increase, even a symbolic one. That would open a split between the moderate Republicans and the Tea Party that the Democrats could exploit. It was a promising tactic but it failed and they are frustrated because it did.
The next factor is how to explain their failure to their base. The left is using the excuse, "We couldn't help it, the other side is crazy."
The final factor is the set-up for the next battle. All along the left has insisted that the Tea Party is a fringe element and that the Democrats represent the mainstream. This is the classic "big lie". It doesn't matter if it is true or not. The idea is to keep repeating it until the general populous believes it. Many Democrats already believe it. The Tea Party has always been incomprehensible to people who see big government as the solution to all problems.
Put it all together and we get an incredible wave of vindictiveness.