OSS projects have already started to recognize that LLM is just a tool and how you use that tool matters a lot more than whether you are using said tool at all. Lets bring StackOverflow for analogy: we didn't ban browsers for code development because one can navigate to StackOverflow and copy-paste some really crappy code. LLMs are SO on steroids (actually trained on SO topics). So grabbing LLM to get a sense of direction or shape is an OK use in general, but copy-pasting it's results blindly is silly and dangerous.
There's a second argument that AI is ruining OSS communities which I believe is true, but refusing to accept AI code is a self-defeating action. Why? Because AI training needs unadulterated source of knowledge, one not tainted with AI and OSS communities rejecting AI would be that source. Also: if OSS community did not use AI it would hardly stop it from continuing it's growth in Enterprise. So there's not much of a winning strategy there either.
Which brings us to GrapheneOS decision and given above reasons I think it's a well-balanced decision.