[restingrobot]

In situations like that, there is no need to engage. The transgressor is being defensive of their actions and I could easily see the same response to saying "we don't do that here"

"Don't do what? Why wouldn't we make jokes and have fun? I was just trying to be funny. Some people are too sensitive. Besides, it's true. ..."

At this point in the conversation, the best course, (in my opinion), is just to move on. It's hard to argue when someone clearly communicates what you did wrong, but people still do it all the time.