It's a decision they've made. Perfectly reasonable. If they did accept AI code, that's perfectly reasonable too. They just made their policy clear here..
I would personally whitelist people with good enough reputation/contribution history. Might get the best from both worlds. Avoiding AI spam while saving time for the core contributors. If they just have capability to use it responsibly.
loading story #49738475
In this time and age I don't think it is a reasonable decision, but sure, their right to make that decision.