I agree it is rude for programs not to give applicants the courtesy of a rejection, especially given application fees...it's not exactly like they're working for free.
Anyway, it's my first time posting here so I'll be brief: I, too, was a bit disappointed and surprised not to receive "informal acceptance" from Princeton yesterday, but I think there's a reason auto-rejects don't post immediately...GS admins could override or DGS could have a change of heart or "priority" as they pertain to institutional diversity initiatives.
As a Princeton alumnnus (masters) and URM, I can speak from experience that URM representation is exceptionally poor among doctoral students specifically, not just at Princeton but nearly everywhere. I'm still looking forward to hearing from other places however and wish much success and happiness to all recent admits. Congrats you earned it!