For almost all typical programming jobs out there, isn't asking a question such as this like hiring someone to flip burgers and expecting them to demonstrate how to butcher a cow during the interview?
I make no qualms about wanting to hire programmers that "get" what's going on down below.
You're right, though, the original question itself is not so much of a problem, I suppose. What bothered me is the subtext that, unless you get down to the bit level with the minimum possible number of CPU instructions in the result and do the compiler's job yourself, you're not a "real programmer" or something.