This is a prime example of poor AI policy. It doesn't define what AI is – is using Google translate in order to engage on their mailing lists allowed? Is using Intellisense-like tools that we've had for decades allowed? The rationale is also poor, citing concerns that can be applied far more widely than just LLMs. The ethical concerns are pretty hand-wavy, I'm pretty sure email is used to empower spam and yet I suspect Gentoo have no problem using email.

The end result is not necessarily a bad one, and I think reasonable for a project like Gentoo to go for, but the policy could be stated in a much better way.

For example: thou shalt only contribute code that is unencumbered by copyright issues, contributions must be of a high quality and repeated attempts to submit poor quality contributions may result in new contributions not being reviewed/accepted. As for the ethical concerns, they could just take a position by buying infrastructure from companies that align with their ethics, or not accepting corporate donations (time or money) from companies that they disagree with.