It's great that you called her and talked to her! It sounds like you handled it correctly, and hopefully you got the answers you were looking for. It's always best to confront someone in a caring way when you have concerns about their behavior. Great job for being assertive. It sounds like you may have helped some other parents too!!
Perhaps there's an article or two that would be specifically relevant to the situation you generally referenced, with tips to support a different approach. For instance, here's one from the U.S. Department of Health and Human Services:
Usually when a teacher yells it's not because students are behaving well. While one would think that teachers can handle their emotions better, we're human and have limits and at times find that to be the only way to get control...not the best way of course, but when that has happened to me it's been out of frustration after everything else did not work.