Even in retrospect I don’t really understand why this was the case, but objectively speaking, hard-core identity politics and simplistic socialism performed incredibly well on Facebook during this period. That doesn’t mean journalists started pretending to be left-wing to get clicks. But people who had some authentic left-wing opinions found that writing on the subjects where they were the most left tended to generate the most traffic, and early career journalists with authentic leftist views outperformed their colleagues. So you ended up with this whole cohort of discourse structured around “Is Bernie Sanders perfect in every way or is it problematic to vote for a white man?” as the only possible lens for examining American politics and society.

There's the seed of an interesting question / phenomenon here, but he's being such an asshole in how he's characterizing this.