Historically, this phrase was used in linotype newsprinting to queue to the proofreader that a line mistake or template needs corrected. The first 2 vertical rows in the linotype keyboard read "ETAOIN SHRDLU".
Today, this phrase refers to the type of sensational, defamatory, libellous or click-baity articles that an obnoxious indie journalist publishes. It's typically an insult.
Donald's entire "in the crossfire" type of journalism adds up to just a bunch of hyped-up Etaoin Shrdlu written about bar DJs he doesn't like.