I think you misconstrued the intent of my original post. I was merely trying to point out that the interview question was (in my experience) based on a very questionable premise.

I wasn't saying anything about how one ought to handle such a situation during an interview.

I totally agree that a response akin to "Your question makes wrong assumptions. Let's move on to the next question." would be completely inappropriate for an interview, or if the same issue arose in a normal work situation.