There's another way to think about it. YC is a club. And one of the rules of the club is that you talk proudly about the club. If you don't, you lose the benefits of the club. VCs don't demand or enforce that type of loyalty.
"That's the power of putting people in business, & believing in people when others don't." That's as true for YC as it is for any VC firm. Sequoia says no. Benchmark says yes. Whatever. I don't think the dude's take is right at all.