I assume the responses are from people who didn't know that and are now offended that they would've flubbed what the interviewer considered common knowledge in their field. I could see someone thinking it's not a relevant question for certain types of positions, but anyone getting defensive about it is a little bit of a red flag. Anyone doing development relying on location services or navigation systems should have a general baseline intuition for how those things work, even if it's only the broadest strokes. If someone feels angry about not knowing this, well congratulations, you now know this and no longer have anything to get defensive about.