This. One million times. Politeness is not a signal and generally a terrible proxy to figuring out someone's integrity. While most impolite people also aren't highly ethical in their actions, the reverse (politeness + unethical behavior) is extremely common.
It would be wise to separate out politeness, by which I interpret every comment here means patiently assertive, and obsequious, where one is a doormat and butler to all.
In that view, is your view of politeness as a bad signal more aligned with obsequiousness or with civil assertiveness?
