If I understood it correctly, that article is about anti-adblock, which denies access if you have an adblock. That is, the DMCA wouldn't apply to adblock, but would apply to anti-anti-adblock.

Yes, it does seem like a bizarre legal theory, since a simpler way to bypass the anti-adblock would be to disable the adblock. That is, it would be a DMCA violation to not block ads, since by not blocking ads you're bypassing the anti-adblock and watching the content!