> what does toggle "left" and "right" really mean?

Nothing, because that's not the point of the article.

It's weird to me that this is such a big point here.

In an actual UI, you will have labels or indicators telling you what the toggle means and what the options are - "Safety door unlatched" vs "Control motors engaged". That's a toggle between two choices and having it a toggle like that would be safer than checkboxes.

Otherwise your checkbox without labels is equally bad UX because what does "on" and "off" mean for an unlabeled checkbox? I could give enough examples from work how vaguely labeled checkboxes like "remote authentication" are terrible UX.