If anyone thinks their black belt is equal to Rafa's they are ridiculous. I do think there's a false equivalence though. Many of the best instructors are world champions, but there are a fair amount of world champs that are also very average teachers. The amount of guys that are like Rafa that can compete at an elite level and teacher at an elite level is not very big. Also there are some competitors that are great teachers but can only teach their style. Guys like Braulio Estima and Andre Galvao may be able to teach any style very well, but there are plenty of others that can't.
I don't think many people are saying that just being a black belt makes them as qualified to teach as Rafa but rather that you can have world class coaches that aren't elite competitors.
I put a lot of effort into coaching and teaching but at the same time if I had a student that I thought had potential to be a world class competitor I would encourage them to leave me for a school like Atos. So maybe there's a part of me that agrees with you.