The main bullet point is that civility is when we agree it's essential to ensure that the "game" of discourse does not come to an end.

Because we want to play the game, we must protect the game from being subverted. That includes protecting the game from subversion by ourselves in the pursuit of our own, individual goals.

Civilization can tolerate cheats: people who agree that we're playing a game of discourse with a goal of cooperation (being truthful, adequately informative, relevant, and clear), although cheats try to break the rules without being caught.

It cannot tolerate "asshats": people with no regard whatsoever for the values (rules?) of the game of discourse