This is actually useful. I didn’t know that generic “you” meant “one”. I always interpreted it as “you the reader” and felt desperate once a week when reading articles like these.

That said, the audience for this is still pretty niche.

(Even the audience for, say, 3b1b's explanation of what a transformer is, is niche.)

My guess is comment meant that in the context of the headline "you" normally would refer to the average Joe on the street; in this case, it means the average Joe who has a PhD in math, CS, or whatever. It all certainly went over my head and probably 95% (or slightly less than that given this is HN) of the people who clicked the link. But I would take the headline as a compliment that I don't deserve.

They're asking what prerequisites would be needed to understand the article.