False. When I was in college, about 8 years ago, Jane Street not only hired from our school, they came to our career fair on regular. I interviewed with them myself at the time for an internship, but fumbled because my combinatorics knowledge was severely lacking at that time, and algo wasn't quite up to par either.
My college was a public state school (Georgia Tech). While it is a great school, it was public and affordable (could be done for nearly free in-state). But it definitely was not some super difficult to get into exclusive ivy club or the likes.
So it seems like they indeer attend a rather wide variety of schools, given the size of their company. But they aren't a mega giant like Microsoft/Amazon/etc. that can afford to directly send people to recruit from almost every school in the US, their headcount was under 1k total iirc, and significantly.