It's unprofessional. If the person who was called princess felt uncomfortable enough to write about it, it indicates they were not friends and this is not their

It's unprofessional. If the person who was called princess felt uncomfortable enough to write about it, it indicates they were not friends and this is not their common relationship. It's can be a disrespectful joke. Besides, it's a gendered joke. If it was directed to a woman, it's very impolite, given the constant pressure on woman to keep thin in society and how that is a frequent bias towards woman. If it was a man, it sounds very transphobic/homophobic, as in "you're less because you act like a woman", besides man also deals with fat shaming. And a lot of people deal with eating disorders, so making fun of people eating choices at work is not a good idea. Of course, if they were friends, I mean actual friends. It would be fine. If one person had felt offended, they would be able to say that to the other, instead of an anonymous mailing list. Or if they didn't felt offended, they could laugh together and each to it's own. But it's clearly not the case. So it's a good idea to avoid this sort of behavior to people that you don't know well, even you get along with them in a work environment. If people feel they need a guideline to avoid this behavior and not feel like they need to be hard pushed to figure out what they did wrong, here it is: you can make this sort of joke to someone who is your friend (friend enough to regularly see each other outside of work, take care of each other kids, trust in each other in personal matters), if not, it's not work appropriate.