It is not disrespectful and she did not say you were stupid. It sounds more like you work slower than others who have done the same job, with the same experience. That does not mean "stupid" at all. It just means slow, or slower than average. Yes, you over-reacted. She was honest with you about why she does not put you on the bar. Would you have preferred her to lie to you? Lying to you wouldn't help you. Now that you know the problem, work on it.
Certified Paralegal, with 25+ years' experience & with Employment law experience.