Obviously, every human-resources staffer and career coach in America would rightly advise against telling a joke like that to colleagues, especially over email. The interesting question, I think, is whether those existing workplace norms are what they ought to be. Would that man’s joke be flagged in the ideal workplace culture?

The question strikes me as extremely difficult. Were I running a startup, where I was responsible for shaping the corporate culture, I wonder how I would handle the situation. In my head, I keep conjuring a debate between a jocular startup CEO and her HR director that illustrates some of the ways that I’m internally conflicted.

HR: I already warned the employee who wrote that email to make sure that he never behaves so unprofessionally again. And I think that we should discipline him. This is a business, not a comedy club. Our investors gave us money to earn returns. We’re paying workers to earn profits, not laughs. That’s inappropriate in a workplace.

CEO: Let me play devil’s advocate. It was a harmless joke. What’s wrong with having a little fun, in passing, at work, as long as you're doing your job well? He’s a capable, well-liked employee and his sense of humor is nothing if not mainstream. Our workers aren’t robots, they’re people, and we ask them to spend more time with their co-workers than they do with friends and family. I can’t forbid them from ever joking with co-workers. That might well hurt morale and productivity. You were teasing me this morning about my coffee order. Was that inappropriate?

HR: I don’t object to all jokes––I object to this joke. You can’t tell me that all humor is office-appropriate.

CEO: No, but this wasn’t a rape joke, or a sexist joke, or a racist joke.

HR: It was a Holocaust joke! There are subjects you don’t joke about. That’s one of them. It diminishes the atrocity and its victims. I get he was joking, but that’s no excuse.

CEO: I agree that “just joking” is a bad excuse, but that’s because jokes carry meanings. That’s what we should judge. It would be wrong to tell a joke that vilified Anne Frank or extolled Adolf Hitler or denied the Holocaust. But this joke is benign and unobjectionable because what it conveys, its actual substance, is something that no reasonable person disputes: Anne Frank would be very averse to Hitler.

HR: You’re intellectualizing it, as if a joke can be objectively inoffensive. But offense is subjective. In the workplace, people have a responsibility to avoid saying things that make co-workers uncomfortable. You can’t know every sensitivity, but any idiot knows an Anne Frank and Hitler joke is likely to upset someone.

CEO: I share that instinct, but the emailer isn’t an idiot and he didn’t seem to know better. Look, I don’t want any of our employees to be uncomfortable, ever. But that’s not achievable. If I go to our staff and tell everyone that they’d better watch what they say more closely from now on, that might make more employees anxious and uncomfortable. Some would prefer that no one ever jokes at work. Others would find that formal, restrictive environment uncomfortable, stifling or oppressive. I agree that we need to use our judgment about humor in the workplace. I just don’t think the right balance is banning any joke that might offend anyone.