You're absolutely right. Your two word snark has really added value to this discussion by clarifying that there is really no reason we should believe that these two things might have anything to do with each other whatsoever. I mean, variables routinely fly up and down by over 100% for no reason.

As xkcd had it: "Correlation doesn't imply causation, but it does waggle its eyebrows suggestively and gesture furtively while mouthing 'look over there'."

Um, okay, so what? Re-read the article. Where, exactly, does it claim that dropping DRM is responsible for the increase in sales? The only thing I see is blurb pointing out that dropping DRM didn't result in everyone copying instead of buying.