Recently I was picking a self-hosted tool for planning trips, and I deleted it after a day, because it was extremely vibe-coded and none of the security issues reported in GitHub were ever fixed. It can be a prompt away to fix those! I noticed this way too often in OSS that is vibe coded, people focus on looks, feels and code does not get reviewed enough, because it "looks good with the CSS gradients" and "an LLM is always right".
So I understand why they would ban and forbid AI / LLM contribution, and I am happy they are banning them, I assume mostly for the mental sanity of maintainers and for making sure that knowledge share and somewhat better PR reviews happens. I will always pick a human-made project over an AI / LLM coded one.