I think that this comment is not interested in any sort of understanding the parent comments, fundamental or otherwise. It sounds like it's more interested in scoring cheap putdown points and signalling superiority.

I'm also uncertain of what, aside from relevance, makes political/social commentary "cheap" as opposed to "expensive", or why the latter would be more desirable.

Perhaps it's based on a misguided idea that commentary must be tied in scholarship to be worthy of utterance (and that such "expensive" commentary is not just a ritualized and impotent form of social commentary). Or that history moves because of such "expensive" commentary, as opposed because of the "cheap" opinions and actions of puny laymen.