Earlier quoted context omitted.
I really wouldn't make that conclusion until you knew what job he was interviewing for. Firmware development? Sure, you might be right. iOS developer? Unlikely that low level bit manipulation is going to be a good indicator of his ability to succeed in that role. That's not to say its irrelevant, but, just not a quality indicator for that role in my opinion.
Maybe Google hires firmware developers, but I think they don't hire iOS developers. They hire "software engineers", and throw problems at them. (Or rather, these generic software engineers migrate toward problems that interest them in the long run.) It prevents Google from having, say, more "iOS developers" than they need when they decide to concentrate on other products. We may debate the merit of this strategy, but…
If I was the interviewer and someone was honest about not knowing about biwise operatoons but was able to ask the right questions to gain some understanding I'd be impressed.