I think that guy got his just desserts there. You don't ask someone to quit just so you can get a card, even if he was to be polite, which he most certainly was not.
I, personally, am always polite. Just because i am the Dark Gentleman doesn't mean the Dark part has to set in in a game involving someone who doesn't share my taste for Roleplaying during a game. Not many people ever do, so I don't do it so I don't weird people out or give them the wrong impression.
I only require myself to make two posts in the chatbox regardless of whether the person will speak to me or not:
"Good luck to you, sir/madam."
"Good game, sir/madam."
...and that's it if they don't type anything. If they do, I be polite by responding courteously unless the opponent is spewing flaming remarks at me, in which I play along and weird them out and make them feel insecure and guilty. If they're someone like Grain here who I have played against once or twice, I'll start up pleasant conversation about game strategy and make commentary on my own thoughts because my feelings against someone who I have friendly conversation is pretty much as if I was playing across the table with real life friends of mine.
That, dear friends, is how you use proper etiquette when speaking in a game to a friend or a stranger, and how to weird out the garbage that flame you.