Are 1201 takedown notices even supposed to be a thing, or were they just invented by the RIAA and/or other overly enthusiastic copyright holders? I was under the impression that DMCA notices were for the removal of infringing content, not alleged anti-circumvention tools. That's what the law seems to specify. The notification and takedown process is specified for infringement of copyrighted works, not distribution of…
My reading is that the DMCA expanded the definition of 'copyright infringement' to include 'circumventing protection afforded by a technological measure that effectively protects a right of a copyright owner' (§1201), and so a DMCA notice specifying 'material that is claimed to be infringing or to be the subject of infringing activity' (§512) would work for the removal of anti-circumvention tools as well.