Phew, I just took a look at the link you offered, Piers. Not nice.
I suppose it has the same sort of usefulness the Ku Klux Klan songs do, letting you know what kind of mentality you're dealing with.
Reminds me of some of the less likable songs of the Philippine Campaign.
I'd say this is more closely allied to the mood of Abu Ghraib-style atrocity than it is to the sort of "soldier songs" people like Dolph enjoy collecting after the war ends.
Makes me wonder how many such vicious gore-loving hate songs in previous wars may have been quietly dropped after use and never circulated, simply because they were indefensible.
Folk music on the front lines...in as much turmoil as the kids we're teaching to kill. Thought-provoking...or maybe just provoking.