It feels like the author is not familiar with JavaScript, and is taking it out on Ember. JavaScript is a whole different environment than Ruby, not in the least

It feels like the author is not familiar with JavaScript, and is taking it out on Ember. JavaScript is a whole different environment than Ruby, not in the least part because JavaScript provides async code-entry. Maybe that would be causing the direct URLs to fail, as some global state is expected in the child pages, but isn't setup yet.