My personal theory is that this is all because Zuckerberg has a rivalry with Elon Musk, who is an AI decelerationist (well, when it's convenient for him) and appears to believe in keeping AI in the control of the few. There was a spat between them a few years ago on Twitter where Musk said Zuckerberg had limited understanding of AI tech, after Zuckerberg called out AI doomerism as stupid.