Perhaps the most telling portion of their decision is:
Quality concerns. Popular LLMs are really great at
generating plausibly looking, but meaningless content. They
are capable of providing good assistance if you are careful
enough, but we can't really rely on that. At this point,
they pose both the risk of lowering the quality of Gentoo
projects, and of requiring an unfair human effort from
developers and users to review contributions and detect the
mistakes resulting from the use of AI.
The first non-title sentence is the most notable to consider, with the rest providing reasoning difficult to refute.
