More exact to say he blamed the victims AND the Muslim terrorists. He said people who are subjected to baiting and provocation will get angry. He's talking about obscene and sexually humiliating imagery, which Charlie Hebdo used against Jews, Muslims, Catholics, Christ, Israel, as well as all the French Left's politically conservative opponents--- for instance images which would anger us greatly if they were portraying Sarah Palin or Mia Love, let alone Mary the Mother of Our Lord.
Donohue says that murder is not justified, but that anger is. He does not say this makes the murders less reprehensible; he says murder is not to be defended in any case whatsoever. It's even possible that the editor Charb was a reckless narcissist and obscenity monger, kinda like Robert Mapplethorpe perhaps, who similarly amused the Left by desecrating persons and objects sacred to others. I don't know. But nobody says he "needed killin'", so your argument falls short.
But Jews, Catholics, Christians, Israelis and the French Right didn't react violently. So the blame--all of it--goes on the Muslim Terrorists, not the victims.