I think the poster was generally referring to the fact that students who progress at a faster rate will have an advantage by simple virtue of having covered more material in school. They will be more preferred by colleges which leads to being more preferred for jobs. Basically a "rich get richer" effect.
Of course the idea that this is a bad thing (as opposed to being exactly how a merit-based system is supposed to work) is based on presupposing that higher performance was the result of unfair discrimination in the first place.
Of course the idea that this is a bad thing (as opposed to being exactly how a merit-based system is supposed to work) is based on presupposing that higher performance was the result of unfair discrimination in the first place.