I think there is a difference between being polite and being chivalrous. Chivalry is rooted in viewing women as a weaker sex where things must be done for them and to protect them. It sends the message that women are property to be looked out for. I don't hesitate to open a door for a man or woman, and I like when someone is considerate enough not to let the door shut on me as I approach it. I think intent is the key word in these situations.