You're going to have to explain why you think this is incoherent if you want people to argue against your position.
Right now, it looks like you're saying that the first quote's adjectives describe a meta-viewpoint that need not be examined as a viewpoint in and of itself.
Sure enough. I think it is incoherent to stand against a viewpoint of multicultural interpretations of historical events while condemning Facebook's tailoring of news because it hampers multicultural interpretations of current events.
I might have read too much and falsely concluded that the author is against Khan’s “historical perspective steeped in academia’s standard issue, postmodern, left-leaning narrative of cultural relativism, multiculturalism, and moral equivalence.” The OP might be neutral about that, and simply exposing the necessity of balancing Khan’s against a different narrative¹. If so, either his articulation was obfuscated by the choice of words or I need to practice my English a lot.
¹. Never mind the fact that this rarely occurs in real classrooms.
Right now, it looks like you're saying that the first quote's adjectives describe a meta-viewpoint that need not be examined as a viewpoint in and of itself.