> AI writes unmaintainable code - you can see that many projects don't accept it.

There also exist other good reasons why projects don't want AI-generated code, in particular

- because of unclarity of copyright status and consequences of AI-generated code

- because the project leader simply made the observation than many programmers who hand in AI-generated code care more about "getting things done" and "pushing through their changes" (possibly to boost their CV) instead of deeply caring about code quality