Agreed. The concept of “don’t reuse your old work when you’re supposed to be creating new work” may be valid, especially in training environments, but it shouldn’t be called self-plagiarism or treated like plagiarism.
If your goal is to share information, you want quality articles in multiple places so that people can get to them. If your goal is to use journal publishing count as a professional metric, then double publishing becomes unethical.
The modern equivalent would be to declare it unethical to share an article on both Reddit and HN.