Eduard:
I'm sorry, but I think you are creating false analogies.
You might be able to ride a bicycle well. That would mean that you
have some sort of understanding of the physics involved, even though you
couldn't explain the principles of physics to anyone.
You might be able to use language quite effectively and well without really
being able to explain the grammar. You can use grammar without being able
to explain it. One of the reasons to teach rhetorical grammar is so that
students will have a greater understanding of the grammar and they will be more
aware of the choices they can make and the effects they will create. It
isn't at all about being 'correct.'
Linda