False. The Jedi were a tiny group to begin with an at the time of Rogue One there are only 2 left. For most of the people in the galaxy is indeed a myth.
As I said, I don't go any deeper than the movies. Yet, according to the timeline of the movies, when Rogue One takes place, the Clone wars had pretty much just wrapped up, less than a generation ago. I'm on board with the backwater thing, but the movies showed a lot of Jedi in battle during that war. I wasn't born until 25 years after Wold War 2 was over. But denying jedi and the force, just kind of seems like denying the fact that Kamikaze Pilots existed during WWII, there weren't any of them left when I was born.
Anyways, thanks for trying to explain, it still seems like an odd thing to keep emphasizing. I'm only seeing it from the movie perspective though, so maybe that's it.