The thing is that a "very high standard" is not a measurable criterion. The project can have test coverage requirements and strict linting to catch basic syntax

The thing is that a "very high standard" is not a measurable criterion. The project can have test coverage requirements and strict linting to catch basic syntax and logic problems, but how do you enforce simplicity, correctness, robustness, or ergonomics? These are abstract concepts that are difficult to determine, even for experienced developers, so I wouldn't expect less experienced developers to consider them. A code review process is still important, with or without LLMs. So we can ask everyone using these tools to understand the code before submitting a PR, but that's the best we can do. There's no need to call anyone out for not meeting some invisible standard of quality.