> Can you seriously imagine the journal accepting an article even slightly negative about the field?
There are plenty of critiques of these disciplines that come from within. For people with a deep understanding of these fields, there is nuance in them, and argument. From outside, perhaps they seem entirely cohesive.
The truth is it is entirely possible, specifically in philosophy and gender studies, two subjects I've worked in at a postgraduate level, to find progress and disagreement, even with hints of ridicule! Hell, I've been exceptionally critical of some popular views in those fields and come out the other side unscathed.
But the difference between those critiques and the Sokal Squared caper is that it doesn't offer any meaningful critique of the field.
> which is corrupting academic research
This is a politically-motivated, biased leap to a conclusion that the hoax doesn't support. All the hoax showed is that bad papers can get accepted in academic journals in these fields. We can add those journals to the list of journals in the fields of medicine and psychology that have similar problems.