Well, that's a bit rubbish, isn't it? I mean, blimey, you hear all this stuff about how wonderful ballroom is, and now it turns out that the teachers aren't being taught to teach?
Ignoring the merits or otherwise of MJ as a dance form, Ceroc really does work hard on its teaching methodology. Things like making sure the teacher is easily seen by the students, that their explanations are clear, and that you can hear the explanations may not have much to do with dance expertise, but they make one heck of a difference to the learning experience.
In addition, the fact that all teachers go through a central training course means that you get a great deal of consistency in quality and approach. I'm not saying Ceroc teachers are of a terribly high standard, but even the worst Ceroc teacher will be much much better than the worst of the MJ independants (or, in my experience, the worst of the Salsa teachers).
In fact, the "Ceroc = McDonalds" analogy is a very good one. It's not great food, but you know what you're going to get, and you can reasonably confident that a minimum standard will be met. In both cases, the truth is that you could do a lot worse. (Actually, McD seems to have driven out a lot of the really bad British cafes. But I remember that when it came to the UK, the food actually seemed pretty good (and non greasy) compared with most of the local competition).