I think that your reaction to this malpractice by the organizer was completely understandable and appropriate. If you wanted to remain calm and nonjudgmental in the face of this malpractice, I think that the trait needed is not compassion but forbearance = patient self-control, restraint, and tolerance. To have compassion is to have concern, to care about the suffering of others. The organizer does not sound like she was suffering.

With retail customers, they may well be suffering, and that suffering may express itself in rudeness to you. I'm sorry for that. On the other hand, they may not be suffering, they may just be rude. In that case, forbearance may again be needed.

What if you know for a fact that someone is actually suffering? How much compassion can you feel for that person?