That's what I disagree with. In normal English we say two is less than three, someone with ten apples has got less than someone with twelve, and so on. No count/mass distinction is made with 'more', which functions as comparative of both 'much' and 'many'. The relatively rare word 'fewer' just strikes me as a pedants' revival, an artificial and unnatural distinction gleaned out of some obsolete grammar.

The only notion of "correct" that holds water is "what native speakers naturally say".