I think you don't understand how tiring it is to review full-llm code. I think banning it temporarily until people calm down with AI-generated PRs is a very sane solution. If it is still the solution in 3 years, maybe you would have a point then.

I only manage 3 'new' hires and I am of the mind of banning AI usage myself despite my heavy usage (the new hires don't level up, that's my main issue now, but the reviewing loops and the shit that got through our reviews are also issues).