“Your grasp of grammar, quite frankly, is atrocious.”
Totally uncalled for. Hope the “ego points” were worth it for you. Also, when one teaches - truly teaches as opposed to indoctrinates - one often learns as much if not more than one’s student. Furthermore, which is more important, good grammar ability or a sane world view?
I think in spite of my teaching pitfalls, at least he would have been left with his common sense intact!!