I don't see how you overreacted. You didn't really react at all. You seem irritated at having to tolerate what seemed to you to be rude behavior. It seems honest to me, what are you supposed to do, pretend you're not irritated? I wasn't there, but if the principal got defensive then it probably was an awkward question. I don't know I wasn't there to hear the tone of voice, body language, etc.
yea, that's pretty much it, kind of like being expected to sit and eat using proper table manners, then having the person next to you eating with no shirt, dirty and feet on the table and i'm expected to take it and not say anything about it..