I'm sorry you had that experience. No student deserves to be treated the way you were treated.

Mathematics is a deep subject. It requires many hours of study over decades to develop. Students who are struggling deserve to have a patient teacher explain things to them in terms they already understand. Not every student has this experience, however. I have tutored a number of my peers in undergrad and they have complained of similar treatment from professors or TAs. I do my best to help them and make sure they really understand the topics they're studying.