Going by your story, you were 100% in the right. Which is why I'm reminded there are always two sides to a story.
First, he goes absolutely berserk when anybody from outside the club comes to watch/practice with us. We have an eight-degree dan coming, and I’m not arguing that this isn’t a big deal. However, the past practice he dedicated the entire time to teach us etiquette, making the comment, “I’m very stressed. He’ll look at you guys, and judge my teaching.” He then, the next day, sent out a long email point by point telling us what we need to do—such as bowing when entering/leaving the room, noting wearing T-shirts that show, removing a small red string from a shinai—yes, things that we shouldn’t be doing, but he has rarely, and often never complains about—and then a lot of things that are very foreign to us, such as responding, “Hai!” to everything, etc, etc.
Now, I know he technically has the ability to do this, but he did this because he was upset about something I said to him. First, let me explain the club: not a dojo, takes place in a basketball court at a local university. Very laid back, friendly atmosphere.