Sometimes I see people argue that a particular concept "doesn't exist", as a concept is an abstraction over the whole, but all there is to a whole is it's parts.
This position is best described as reductionism, some of which is greedy.
I'm not sure if this disbelief of concepts is really tied to one's use of S function. Continuum fallacy is something similar. People argue that a phenomenon exists in a continuum, like amount of hair on someone's head. It's arbitrary decision to draw the line between a bald man and someone having hair, so they argue it's a poor concept, and shouldn't be used at all.
I've also seen somewhat similar argument, telling that there's no instance of a perfect capitalism in the world, and no instance of perfect communism has ever occured, so there's no communism or capitalism at all.
This "no concepts" belief pleases some people. Disbelievers often point out that the concepts aren't as readily verifiable, they've been made arbitrarily, could be done in a different way, or they don't otherwise satisfy their arbitrary ( !!! ) criteria.
Is this group the S group?