Just the fact that you're ready to go all-in arguing about a detail of small talk and start talking about legality and such, is employability poison. And that's something interviewers are looking for. I agree that it's a weird question, but one that the person being interviewed can easily just pass without it being a big deal.

The other poster said it's just a question to easily filter out applicants who aren't paying attention, and it seems as good a method as any. Say "just a cup of coffee" and move on. If the interviewer continues to talk about breakfast or other irrelevant stuff, then I'd just end the conversation. But they can have one for free.

But on the subject, I have no idea how companies manage to screw up their hiring process this much. I used to sometimes interview and hire people and found it to be the easiest thing ever, and I never had the need to do these weird games or more than a phone interview to find great employees. How hard is it to just focus on the exact task of the job and find a candidate who understands it and has a good attitude?