I wouldn't judge based on the limited context we've provided.

I've interviewed candidates for jobs requiring highly specific skills who claimed to have those skills, but in the interview they kept trying to divert the topic to something else. An analogy would be bringing someone in for a C interview and they keep trying to write all the answers in Python and pretend that C and Python are interchangeable.

So some times, asking the candidate if they know what they're interviewing for is really called for. You want to be sure the person understood the interview, not that they were confused by the questions.