Are these violent episodes in any way Glenn Beck's responsbility?

Yes, people like him, Rush Limbaugh, and Sarah Palin, who make a living catering to the violent tendencies of right wing extremists, should be held accountable for inciting other people to commit violent acts. These people are the American counterparts of extremist Islamic clerics. There is little difference between a video of Osama bin Laden shooting an assault rifle and some of the right wing politician videos picturing them shooting rifles.