My cofounder and I applied and were accepted with exactly zero connections to the Valley and effectively no YC connections (one friend of a friend was a YC founder, but we didn't end up getting in touch until after we'd gotten in). I doubt that's the norm, but we're proof that it's possible.

If we'd been smarter/less naive, we'd have cold-emailed one of the dozens of YC founders who publicly state they'll chat with people who are applying.

Even if that were really true, the post itself offers you the opportunity to know someone on the inside - "shoot us an email with any questions you have about YC". What are you waiting for?