That's funny right there.
I try my best as an instructor to never misspeak or misinform. However, I am sure it can happen. This however doesn't seem to be the case here. I have heard some strange things coming from instructors. I occasionally will say "Instructor hat off" and then make a comment when asked a "what would YOU do question". I have cut way back on those comments since anyone not paying close attention or walking in late on the conversation could take things out of context.
Like the time I was teaching a class and another instructor was teaching in the room next to me. I had to walk through his room to get something right at the time he was telling his small class to come to his house when the a problem arises because he had plenty of weapons. LOL I am sure he does.
To the OP, I think you were right to point out the situation, and I am sure you did it respectfully, I would just be careful with pointing things out in front of everyone else. I will say however that I would have a hard time not doing so openly. I have had to leave gun shops and Academy when I heard stupid information being dished out. If I can't correct quietly and respectfully I leave so I don't make an A** of myself. I have been known to pull out a book and show them.
I keep extras all over. LOL