If you were to trace lines of argument from where 1980s middle-class activism (on racism, sexism et al) met 'Cultural Theory' in UK universities you'd see how ideas about Queer Theory, 'Subjectivity', postmodern possibilities, rhizomes, laughing medusas and so on, followed a trail of internal logic whereby existing boundaries and boring old categories could be kicked out because they're as uncool as your Mum and Dad. I was part of this minority-interest fun, but still can't quite see how it spread so widely outside certain subject-areas although it does coincide with the great uptake of students post 1992.
But, it's the spread and take-up of these ideas, sometimes half-understood, with all the original debates removed, in application to the real world via vocational or would-be vocational subjects, then to become embedded in institutions and management structures which has at least partly led to of the current situation.
Academics have been gently simmering in this for so many decades and generations that an unspoken agreement on categories, oppressions, language, 'progressiveness' and so on has simply become the new common-sense. It's become the orthodoxy in how to get on at work, how to get grant funding and how not to get into trouble. It's become belief. Student-customers don't really question it, having been taught it by new generations of academics who can't remember the old debates or contexts.
Universities don't prioritise critical thinking or debate in any area where they might be socially and financially punished for wrongthink but reassure themselves that all the ideas about categories and oppressions they buy into are just settled facts among their own class, so no questioning is needed. In my experience, academics don't have any special powers to get them out of stupid thinking and its consequences.