AI assistance doesn't necessarily imply lower code quality. It can help with improving it in a lot of ways. Full vibe-coding without careful review is what results in low quality code. I think a lot of projects are having trouble getting to the sweet spot, though: if they allow LLM-assisted contributions then no matter how much they write to try make sure the result is high quality they're going to be inundated with far more low-quality contributions and have to work harder to filter through and reject them than if they just have a blanket ban which then makes it a lot easier to reject everything. The linked discussion is specifically with a view that not all LLM assisted contributions are bad but that they need to stem the flow for now and figure out how to open up afterwards.
I recently started using Claude and I found it great that Claude is constantly writing tests since I did not due to lack of time. That said, Claude has this ability to reach into test harnesses and output all kinds of obscure syntax and language features that the tests are hieroglyphic. I'm pretty much like 'ehhhhh ok claude, you do you...i'm just going to keep writing the business logic over here..."
I haven't actually looked at any open source project PR queue, but what is the ratio between actual thought out LLM assisted PRs and vibe coded PRs that are spammed unread? My bet is 1:100.
Not to mention that the thought out LLM assisted PRs won't even register as LLM assisted PRs...