While I believe that the tutorials for frameworks do not replace the official ones, I still find great value in having them available on MDN. Perhaps you are not seeing this because you are viewing the problem from the perspective of someone who already knows very well what these frameworks are and how they should be used.

I remember clearly how years ago MDN taught me what libraries and frameworks are and why I should (or not) care about them. I didn't have a CS background nor anyone to teach me. I would probably have been too intimidated to approach them if it weren't for MDN guiding me. I'm very grateful.