That's a reasonable perspective but the assumption I would be making isn't that they haven't thought it through, it's that they're using a higher bar for what's

That's a reasonable perspective but the assumption I would be making isn't that they haven't thought it through, it's that they're using a higher bar for what's necessary, and are thinking it through from that point instead. The dialog is then about coming to a shared understanding of what the actual requirements really are. Therefore it's not critical or something to be taken personally about one's proposed implementation, it's the symptom of unclear requirements and the need to clarify them.