"The Roots of Metal" Project

For the record, I don't think that "After Forever" is a metal song at all (i.e. it's more of a heavy psych/hard rock number in my opinion) but "Sweet Leaf" certainly is & it's predominantly centered around the modern-day understanding of the stoner metal sound as far as I can see.

This person's argument is completely invalid really. Stoner metal is not a scene. It's a subgenre. Only scenes or movements can be governed by limited time slots in history. For example, you could say that Iron Maiden's "Powerslave" isn't a NWOBHM release because it was released after 1983. If a song or album fits the technical requirements for it to be labelled as stoner metal then there should be no reason why people should feel shy about doing so. There are plenty of examples of new subgenre tags being created that encompass large chunks of historical releases. For example, we only recently admitted that there is justification for a dissonant death metal subgenre at the Academy but that doesn't mean that there were no releases that had that sound prior to that realization. In fact, it's impossible for a subgenre to become necessary if there's not already a reasonable scope for it to cover. The fact that this scope goes back so far in the metal journey is irrelevant really. It's my honest opinion that if half of the legitimate "heavy metal" from the early 1970's was released today then a large chunk of it would be labelled as stoner metal so it makes perfect sense to me that I should tag it as such.

 I was only referring to Sweet Leaf myself, Daniel. There are loads of examples of genres being backwards compatible. One example is Discharge weren't called D-beat when they started, they were termed Second Wave, like GBH and The Exploited. It wasn't until others started using the same drumming patterns that the D-beat genre name was coined. I'm also pretty sure that Cocteau Twins weren't termed Ethereal Wave and The Smiths weren't tagged as Jangle Pop until much later either. 

As most of the very early heavy metal came from the psychedelic scene, it had far more in common with what we now term stoner metal than the heavy metal of Maiden, Manowar or Mercyful Fate.

I would point out that every description I've seen of stoner rock and metal is that Black Sabbath is one of the primary influences. It's really not that silly that something that was an influence on a genre has a song in that genre. You could also say that Black Sabbath isn't Heavy Metal or Doom Metal either, considering that it took about a decade before those genres got going too.

(and I say this as someone who has absolutely applied strict time definitions to actual scenes like NWOBHM, it ain't the same thing)