It's fairly obvious that engineers are not fungible, and that an entire process centered around that idea, is not only degrading and disrespectful, but an outright lie that needs to be propped up by illogical thinking, and faith-based arguments.
I'm not sure how you determine what is true, but using empirical evidence and sound reasoning is how I prefer to be presented with justifications for a process change. So far, I haven't seen any research showing that agile is an effective management system.