a "teacher" that puts you down isn't there to teach, but to give themselves an ego boost.
If you have specific concerns, I would address them with the teacher. You paid the money, you have a right to certain expectations and to be certain those are met. If the teacher is intractable, then I would walk. But at least I'd try. You quilt because it brings you joy, no matter the technique. If the class is turning that into a chore, then it's counter-productive in my opinion.