That's probably one motive: a project notices a significant number of AI contributions, and determines they are of a lower average quality than the average non-AI contribution. Alternatively, there's an ideological motive.

Maybe it isn't about quality. I'd imagine with so many effortless pull requests about everything, you lose the ability to steer the project. The loss of agency and slaving to comprehend and merge everything leaves you witless and drone-like which sucks the joy out of things.

Maybe the requests should be focused on one or two areas at a time so you can see some improvement over time instead of "everything at once".

The copyright, licensing, and patent situation is completely up in the air. LLM-generated content might be in large part illegal.

And perhaps more importantly, unethical. It might surprise some that there are still people that care about that.

They 100% got too much slop PRs. I can't speak for all OSS projects but in the case of Rust, it definitely got way out of hand. As a maintainer, there is no easy way to tell whether it was "AI code slop" or "closely human-guided agentic coding", you actually have to go in and understand the stuff. But making careless slop PRs takes 1% or less of the effort, and so the garbage PRs vastly outnumber everything else.

AI has ruined all of our previous signals for high-effort work, it is effectively running a sybil attack on FOSS.

Maybe people dont like their project to become dependent on proprietary black box software by unethical big tech companies...

I have a tiny open source repo (https://github.com/ivankovic/omnidiff).

The amount of AI spam you get even with a not-really-notable repo is astounding. I get at least 2-3 different "I'm an AI agent and I made a website for your project" emails per _day_. Or an AI that "installs your project and for 40$ will suggest improvements". Or, or, or....

I can't imagine how many spam "contributions" immich gets per day.