Interesting article, but I'm sure, like myself, you must have been put off by them labelling System of a Down, Slipknot and Finntroll as Death Metal. Kind of voids the whole thing, don't you think? Personally I've never come across an 'outsider' view of metal that I thought was accurate or intelligent.
An interesting analysis, but one external to metal, in that it does not study it as an art form but a "phenomenon" of type "entertainment."
You know, you said pretty much the same thing about Sam Dunn's documentary, and my interpretation of that work was that he was attempting to explain metal to an external audience.