Is that a bad thing? MANY of these projects ban PRs made with LLMs, without explicitely mentioning being against AI in general. Since AI drastically increases how much code you can write, they might not need LLM contributions from outside - they can just prompt themselves.

In that case, only getting a few, hand written PRs could mean getting fewer, but higher quality contributers.

Other projects might not care about getting many contributers, many stars or being widely used. It might simply be a small project someone wants to code by hand. That's absolutely valid, many people still have fun coding by hand.

The truth is just that there are a lot of slop PRs currently, where ppl just sicced an LLM on a problem, did not validate any findings, did not check the code, did not read the output and just acted as a meat proxy. In many cases, these bans on LLM PRs are simply a reaction to this flood of PRs. After all, as I said above - everyone can do those prompts themselves, they don't need a PR for that.