Bad Timing Creates a 'Doonesbury' Dilemma (washingtonpost.com)
While I understand people's sensibilities are raw over the brutal execution of Nick Berg, I do not see how a fair reading of this strip could discern an allusion to Berg's murder. It's very obviously a literal illustration of the phrase "handing him his head on a platter."
(It's nice to see Garry Trudeau making a pitch for justice in the workplace.)