The article, which presumably was written by the authors on its byline rather than by the NSA, says that. The actual config file, linked from the article, at http://daserste.ndr.de/panorama/xkeyscorerules100.txt says:
/*
These variables define terms and websites relating to the TAILs (The Amnesic
Incognito Live System) software program, a comsec mechanism advocated by
extremists on extremist forums.
*/
Linux Journal is listed there, as a ‘website relating to TAILS’, not as an ‘extremist forum’.
4'th bullet point from the top in case you wish to check again.