It's not helpful to simply call the commenter out on not reading the article. First, it's unproductive, and second, it's merely conjecture. Perhaps you both read it but interpreted it differently? It would instead be more productive to point out why you think the person didn't read the article, thereby furthering discussion.

Notice that to get a "step" plot it is necessary to assume that probability of getting an A is strongly correlated with the SAT score. The paper says that for humanities there is no strong correlation.

On the other hand, the "result" for physics is an elementary consequence of repeated trials (binomial distribution)