LLMs can spit code-alike outputs 24/7, faster than humans can read it. This is a DoS attack on open source.
A maintainer can't trust that the person submitting a PR has properly reviewed the code, so they have to do all the review work anyway. There's zero benefit. If the maintainer wanted LLM-generated code, they could ask an LLM themselves, and skip the trust issues and slowness of dealing with a random middleman submitting it.
Something's gonna break.