It's quite obvious from your very own quote that it's the author of the article who's confused about the three (!) different notions of unindexable contents lar

It's quite obvious from your very own quote that it's the author of the article who's confused about the three (!) different notions of unindexable contents larger that the indexable one (deep web) vs. anonymous p2p file sharing networks (darknets) vs. Tor hidden services. I'm tempted to call this "a confusion hat-trick". ;-)