Okay, what other concerns does he mention? All he says is that being fired is difficult...which he then suggests is important because you can then be rude to your boss. No other reasons are used to support this idea.
You're attaching a very unreasonable interpretation to the term "talk back". It's not a pure desire to be rude to people; it's about being able to voice contrary opinions, without fear of unfair retribution and if necessary, without being constrained by political correctness or a corporate culture that demands obeisance. No employee should ever have to fear getting fired for speaking up about something that seems illegal, dangerous, or just plain stupid.