But if you are being rational, you should avoid contradictions--that is a norm. If you are being moral, you should avoid doing unto others what you would not wish done unto you. If you are playing chess, you should avoid placing the bishop on a square that cannot be reached diagonally from the current one. No-one makes you follow those rules, but there is a logical relationship between following the rules and playing the game: you cannot break the rules and still play the game. In that sense, you must follow the rules to stay in the game.

Are you asserting that being "moral" is just like a game with a set of agreed upon rules? That doesn't fit with your earlier claims (e.g. this remark)and on top of that seems to run into the problems of people not agreeing what the rules are. Note incidentally, that it is extremely unlikely that any random intelligence will either know or have any desire to play chess. If you think the same applies about your notion of morality then there's much less disagreement, but that doesn't seem to be what you are asserting. I am confused.