Quantum field theory, with its strange problems of the identity of a particle is hardly materialist and pragmatic. String theory, with its extra dimensions and its paradoxical dynamics at tiny scales is even less so. And the comparable domains of mathematics, like the study of infinite ordinals are just as silly as Critical Theory or post-structuralism. But the problems are just not solved. We want to know how things with very little practical application work out in detail. We want to have an understanding of whatever we can manage to understand.
Picking on the silliness of philosophy, which in many ways addresses far harder problems, is just bias. There is still no materialist, pragmatic solution to issues of real morality, that does not just throw out the problems it doesn't like. Theories of value like post-structuralism are attempts to build an understanding of why we choose the judgments that we do, how those evolve, and why we bother. You can go ahead and simply adopt a solution, but to find one that actually works, in detail, is not a trivial endeavor.
The fact that they don't come together without a ton of fluff and nonssense should not open them to bizarre accusations. There is a lot of fluff and nonsense involved in caring about the mass of the Higgs boson, and imagining that the strange patterns created by that huge ring in Europe will tell you anything is really just more nonsense, taken out of context.