The hypothetical "someone" in my sentence (a professor or a student) is indeed probably male if I look at him closely. I pass no comment on whether professors or students _should_ generally be male; but at the same time, have no qualms with imagining them as such. I understand that many think differently, and have seen plenty of texts where an imaginary character of unspecified sex is introduced with a third-person singular feminine pronoun (a random example: "For a Product Owner to properly adapt a product, she needs some empirical evidence, something to inspect", from "The Professional Product Owner" by Don McGreal and Ralph Jocham). My argument is that if should be perfectly fine for a writer to use the default gender that he is most comfortable with.