Very confusing statement. It is definitely true that OSS is on the verge of a crisis because of AI agents, but they clearly said AI is not the reason to reject external contributors: "Whether code was typed by hand is beside the point."
If AI is the problem, the solution would be introducing an AI policy, community trust management system or something like that. Definitely not a closed development process.
How would they know for sure if the submitted code was written by a human or AI? If they had a “no-AI” policy, there would be no way to enforce it.
The policy makes sense to me given the security concerns for the project.
There's a big difference between a well considered high quality contribution made using AI as a tool and "claude find and fix an issue in this repo so I can put on my resume that I contributed to a high profile project". The problem is that it takes considerable time of the reviewers to filter out the high quality contributions vs the low quality ones.
I do think closing off contributions is a big step and would rather most projects find a middle ground, but it's definitely understandable why they did this.