Here is a distinction I would like to make. There is a difference between responsibility and understandability. My point is Beck and Limbaugh are in no way responsible for the actions of people who commit violent acts in the name of conservatism (not that many events fall into this class).
Just as a father who beats his son, is not culpable for a son who goes on to beat his own children. That son needs to learn to make life decent, even if he was given an indecent life. People need to move past the indecencies of their own lives, and stop making excuses for their actions. We as a society should do the same.
Now when people have crappy upbringings, I understand that they will have moral short falls. Their actions are UNDERSTANDABLE, but that in no way diminishes the responsibility of the perpetrator. Nor does it ensnare the people who were harmful to the perpetrator in the past.
Is this difference that I am drawing between Responsibility and Understandability clear? So when a terrorist kills in the name of Allah, his actions are sadly understandable, but he is still a bastard and should be hung from the highest tree! Because he alone is solely responsible for his actions, not his Imam! Catch my drift?