> I have an exceedingly low opinion of the institution that is social science
Obviously you don't mean social sciences, but psychology and sub-disciplines (or i hope you do).
> They ostensibly exist solely for propagandistic purposes, pushing an agenda of leftist orthodoxy.
Psychology? Not really, did you work, or do anyone you know work with publicists, or in the moviemaking field?
I think you have a really biaised idea of the psychology field.
For the "leftist orthodoxy" part, i think you're talking about determinism (and indeed this is a founding idea of the orthodox left, and one that the liberal left use but avoid thinking about, as it destroy the idea than merit have anything to do with success, and bourgeois have issues with this idea usually).
Determinism is closely related with sociology and philosophy (maybe that's what you mean when you talk about social science?). The "There is no free will" advocates are taking determinism to its extreme (and have a narrow view of the meaning of "free will" for the overall population) and can rattle people. But i think the reason you don't like this is because of this association: the largest contributor to the sociology field when talking about determinism is Bourdieu, who inspired Foucault and Deleuze. Who inspired the postmodern "french theory" (english term, quite reductive tbh), the term "deconstruction" and are at the centerpoint of the postmodern "gender studies" and "decolonialism". Which are at least controversial and unscientific as it can be, closer to philosophy than sociology but still claiming to be the later.
But you can't throw everything in one block. Without this idea of determinism and deconstruction, linguistic and history would be miles behind (and maybe other social sciences too, but those two i take interest in). If you're right-wing, you can even claim that Furet and disciples deconstructed the polite, unchallenged global view of the French revolution before any postmodern historian, and that's why the field advanced as much this last decades.