Nugent made no death threat. He was likely using a bawdy metaphor as an invitation for the former president to provide him a bj, when he said he should, "eat my machine gun." That might be a paraphrase.A death threat is a death threat and Nugent has a history of advocating death upon political rivals, on many occasions.
I have no issues with protesting a political figure, but I do have issues with the WAY too many protests are made both from the Right and the Left.