I wonder whether the motivation is really legal? I get the sense that some projects are just sick of reviewing crap AI submissions
This could honestly break open source, with how quickly you can generate bullshit, and how long it takes to review and reject it. I can imagine more projects going the way of Android where you can download the source, but realistically you can't contribute as a random outsider.
Quality contributions to OSS are rare unless the project is huge.
Historically the opposite of quality contributions has been no contributions, not net-negative contributions (random slop that costs more in review than it provides benefit).
No it hasn't? Net-negative contributions to open source have been extremely common for years, it's not like you need an LLM to make them.