If I'm reading this correctly, you think juniors should live without formatters because they need to learn to format manually?

I entirely disagree. Juniors have to learn so many more important things - how to logically structure code, testing, working on teams, git...

Why take time away from learning those (and similar) concepts to teach them something a tool does well and, if necessary, they can learn later?

I like it to deciding to teach teens how to drive with a manual transmission instead of an automatic one- they need to be able to drive and not hit things, and the more we can simplify that, the happier we all are. If needed, some kids can go back and learn how to use a stick shift.