But here’s the thing: the standard (like all standards) is obviously not robust enough to physically prevent responses which incorrectly indicate permanent failure.

These incorrect responses could be caused by mistakes which the remote server admins could reasonably avoid, like software bugs. I understand not having much sympathy for that case, especially from an organization with no shortage of resources. But they could also be caused by, for example, hackers or governments exerting control over the remote server temporarily.

A standard which explicitly refuses to acknowledge these possibilities is not what I would describe as “robust.” An obvious better alternative would be to set some standards around what constitutes a polite retry policy.