The amount of energy that this takes up is ENORMOUS, especially when you're dealing with something as difficult and dangerous as the slave trade. And what do you do when the new terms you've chosen all of a sudden become not acceptable?
If we agree that many types of non-threatening speech are no longer allowed, it becomes almost impossible to talk and convey ideas, especially in high-stress areas like this one.
Imagine a medic who waits to treat a homeless person who has overdosed because they can't remember the politically correct way to refer to the person, and they need to radio into the command center first before they begin treatment. So the person dies because the stressed out medic couldn't remember the politically correct terminology because they were trying to work out the best course of treatment...