(Armovore's site registrar is Internet.bs.net, which has a red text notice at the top of its home page that reads "We do NOT support SOPA." It's not clear if people at PaperStreet or Armovore know that.)
That's not terribly unusual for a pron company, but Armovore is not a pron company. It's a theoretically legitimate copyright-protection service. A company in that business should only be worried enough about its own infamy to try to avoid being found if it were up to something less legitimate than the straightforward issuance of copyright-violation notices.
In addition to the obviously bogus allegation that Techdirt violated any of the teen action at TeamSkeet was another alleging this TorrentFreak article about the Department of Homeland Security accidentally knocking 84,000 sites offline by targeting a free DNS provider in a probe of content piracy and child pron.
The site DHS was really after was just one of the sites using the DNS service, which had nothing directly to do with the crime.
At Techdirt, Masnick sees both entries as covert attempts at censorship using a technique that might escape the notice of even the content owners. If Masnick hadn't been searching for something else and noticed the missing search entry he might never have realized the article was missing from Google's index.
Google doesn't notify sites of allegations they'd violated anyone's copyright before deleting the site from its index, partly because there are too many such requests, partly to avoid being put in the position of judging copyright, which no sane company wants to do.
Given the lack of notice to the victim or any requirement that a search or other third-party site investigate DMCA takedown notices before complying, it's not surprising there would be a lot of mistakes.