It's likely not all this, but i expect an element is: there is a meaningful number of people essentially refusing to work with AI.
Antidotal but I have spoken to friends at Google who are telling me many co-workers say "I tried it didn't work, ill do it myself" when really they just didn't try very hard at all.
Does it matter how someone gets their work done as long as its done on time? Why does using a specific tool matter?
That would be a stupid reason to fire someone when the jury is still out on the net productivity benefits of using AI to code at scale.