Comment by voidUpdate

I think the main functional reason is that because a human hasn't written the code, its potentially more likely to have subtle hidden bugs that a human cant explain because they didn't write it, as well as large pull requests that have to be validated by a human when smaller human written ones would be better. But I think it's generally the non-functional reasons that projects are rejecting LLM-generated code. Some developers just find LLM generated code icky, and would prefer not to be associated with it