I don't think people "need" this to be explained to them. By now we have had decades of "show us the code" and "pull requests welcomed" responses from free and open source software maintainers. Now that people are sending code, it's somehow detrimental to their mental health?

I respect their sincerity at least. It's better to know up front when the maintainer isn't actually interested in engaging with you. Nothing's worse than sending a patch in and not even getting a response.