Linguaphile, alluded to it.
I believe the reason is because,
When you begin to teach grammar, you suddenly are actually
using a plethora of examples, new vocabulary, similes, and complex ideas
that are beyond the students' perceived learning level.
Now that is my teaching and learning method.
So I naturally assume that this complicity acts as an inhibitor in Group Learning,
which results in a standardized, yet really - uhh... - inebriated methodology.
The Key to good learning is to not patronize your audience by treating them like they are incompetent.