That's a bunch of BS. Of course YC wants companies to raise additional funding, grow quickly and exit. That's how they make money. They just do it in a less obvious way - but if you watch their videos, read their blog posts etc. - they're all about hypergrowth. I mean, they even have a VC pitch deck template.
Serving VC pitch decks doesn't mean they want want hypergrowth + exits. Having just gone through the W22 batch - it really doesn't feel like they encourage growing quickly and exiting.
Hypergrowth is often what founders want. It's validation of product market fit (and of all the efforts).