In this case I think you're getting worked up over a relatively rare event. It's not exactly a display of the highest levels of professionalism, but if your F/O has to listen to this type of irrational ranting about the "unprofessionalism" of a bit of light humor, he's probably more inclined to turn down his intercom before box 2.
On the other hand on a nice day in the UK and 121.5 becomes unbearable as every PPL in the country seems to be doing a practice PAN or attaining a location fixes. It's great that they practice with a real controller but maybe assign a freq specially for it, 125.55 for example.