This equating of manners to a submissive posture is odd to me. One wonders what is meant by "manners". Saying yes, please, thank you, and holding a door are by no means submissive acts. Table manners, or not acting boarish while dining, is not submissive. Conducting oneself in a respectful, cordial manner is not submissive.

However fawning and currying favor may indeed be submissive, but are not proscribed by any idea of "politeness" I am aware of. Excessive accommodation to the detriment of yourself and your interests would also be submissive in my view.