That's a bit of a cop-out, since anyone can say it's a top priority on their app. Except not really: Drew was from MIT, and therefore had a large pool of potential cofounders to select from. Most people don't.
It also feels true to say that YC was more squeezed for talent back when Drew applied. Nowadays YC can afford to reject startups for not having two cofounders from the start, especially in borderline cases.