I'd say the fact that they write-off repeated examples of existing systems that are deployed commercially failing, and then also haven't responded with any real world examples of systems that are "nearly foolproof" as a pretty good indicator of arguing a hypothetical.

No he doesn't. His entire comment history is exactly what he's done here. Decently written but empty and contrarian for the sake of it. Engaging with this person is a waste of time, I was merely providing a public service to others that similarly value their time.