You weren't just asked 30 questions. You were asked 30 questions and evaluated on dozens of other non-answer based factors.

Imagine: I walk in, get 27/30 and then proceed to be a sexist bigot who says I refuse to work on a team with gays or women and I decide to start claiming that you have to get 100% to get hired.

I'm not saying you did something like that, but you're just automatically assuming that that question was the pinnacle of your rejection and not the other things listed.

I mean, unless you've been implicitly implying that you're a perfect interviewer minus the 3/30 you missed...