There's shades of gray here. One of the issues of threatening to fire a subordinate is that you very much can, that being fired is a high anxiety issue for most

There's shades of gray here. One of the issues of threatening to fire a subordinate is that you very much can, that being fired is a high anxiety issue for most people, and even if they have thick skin you're still moving towards a more hostile environment. I have thick skin, but I'm still going to treat someone who is joking about my livelihood negatively. That's a separate issue from someone being triggered or emotionally hurt because they read a book or a professor talked accurately about a historical event. That's a case of not being thick skinned enough for reality.