@MontereyJack,
I haven't ruled out native speakers, MJ. [Only those with limited reading comprehension skills; MJ, back of the line.]
The point is that native speakers who do not get themselves up to speed on how English actually works should be banned as EFL teachers. The problem with that is, EFL is a business, and language schools are often willing to take anyone, as long as the body is still warm. You could likely get a job, MJ.
Non-native speakers are no different than a large chunk of native speakers. They both teach prescriptively because it's easy to do so. When all one has to do is memorize some simplistic falsehoods and spit them back out, it makes teaching really quite easy. I've seen large numbers of completely incompetent native speakers teaching English.
Take another peek at the Pet Peeves thread.