How about the reason he just explained? Do you disagree that relying on AI to make changes without knowing what it's doing makes you a worse programmer? How would it not?
If you don't know what a good or a bad approach to any problem is because you've never actually had to solve it, you can't even know what being a proficient programmer means, so how could you hope to be one?
If you don't know what a good or a bad approach to any problem is because you've never actually had to solve it, you can't even know what being a proficient programmer means, so how could you hope to be one?