What generalization? Since we've moved into our new house, 3 1/2 years ago, we've had approximately 30 or so religious proselytizers come to the door. This doesn't include the times I've encountered them while out walking the dog or to the mailbox. The proselytizers have primarily been Mormons, but have also included JW's, as well as people from a few Christian denominations from local churches.
I'm always civil, polite, and friendly when I answer the door. When they start their spiel, I inform them that I'm not interested, and wish them a good day. On perhaps two or three occassions, the proselytizer left at this point. In my book, any continued proselytizing at this point is already pushy and rude. On at least 10 occassions, I eventually had to physically close the door in the person's face after several attempts at telling them I wasn't interested.
Now, they almost always keep a smile and a friendly demeanor. But, when someone tells you "no thanks, have a good day," and you don't leave and keep talking, you're being rude. I realize other people may be confused by the smiles and not realize the person is being rude.
Now, to be fair, I've had similiar experiences with the people who walk around trying to sell new windows and security systems.