If you think someone is an idiot, then this is for you
Don't argue with idiots. They'll drag you down to their level and beat you with experience.
Differences in opinion should not degrade to personal insults. Jerry's method is not universal. By looking at what he wrote on his blog, I probably would not go to his class. IMHO, he is not speaking English even with a near perfect accent.
Your efforts on correcting accent is certainly respectable. Keep up your great work. I am pretty sure you will achieve a lot. I would dream to be a member of your study group yet impossible. Any call in number ? :)
Life is too short for trading bitter words. I encourage you to keep your head high and do what you think good for youself and enjoy the journey. Never mind what others say. Because when you make progress, everyone at this forum sees it.