So OP made his point. You responded by saying what he said was stupid and deserved a stupid response. I advised that was a rude response and you wouldn't do so to someone in person. You responded by saying you would and fact prefer it. So you advised that you frequently call people stupid without having been offended personally. I would say that's a fairly unpleasant way to conduct oneself.
Not at all. I quite clearly said that I don't consider OP to be stupid. But if I would call someone else stupid I would rather do it to his face than on an anonymous internet forum. First, because it's impossible to tell if someone is stupid based on an internet thread and second because it's only fun when you can see his face. How you jump to the conclusion that I frequently call people stupid without being personally offended is beyond me and a pretty rude accusation.