Undoubtedly this is true, but it's also undoubtedly impractical. Check this out, it's even worse than you think: I'm not someone who really hungers for authority. I don't seek it out. Some people do, and I'd guess from my interactions with them that they have even more of this unfortunate trait than I do.
Even without that, I doubt there are enough qualified people in the world who are completely lacking in vindictiveness to fill the positions of authority that have formed as a result of the grand accumulation of human interaction. So, bearing that in mind, it's typically best to be polite to people who can hurt you.
More to the point, the degree to which any human wants to hurt another depends on their emotional state. Impoliteness tends to destabilize it's recipients' emotional state.
Perhaps. Perhaps they will pick on the meeker instead of the stronger, the darker-skinned instead of the caucasian or the female instead of the male. Not all bullies are alike.
Even without that, I doubt there are enough qualified people in the world who are completely lacking in vindictiveness to fill the positions of authority that have formed as a result of the grand accumulation of human interaction. So, bearing that in mind, it's typically best to be polite to people who can hurt you.