Russ Nelson had the quaint view that "I always thought that the quip "Marxism is dead everywhere but on the American college campus" was a cheap shot". Apparently he's just had his eyes opened. Fundamentally, this is an example of a much larger problem. Whatever mechanism we used to have to clean out the phrenologists, the claptrap artists has broken down, and broken down badly when it comes to marxists and their follow ons. It's positively pernicious.
By its very nature, getting rid of false areas of study is horribly difficult in a society that values diversity and freedom of inquiry. At a certain point, the detritus of persistently failed ideas does have to get cleared away. So how do you do it? That's the point at which we seem to be stuck.