If the rules are a general assumption, then that is understandable, even self-evident. But what if these moral rules are a matter of dispute between two groups, meaning that only some of the players use them? In such a way that, in my personal opinion, it would be better if everyone played without those rules, because they really affect the game negatively—and that is the dominant view among the players there from medium-high rating and up—but I happened to get into some game with a noble moralist who affected me by his good morality out of his view that this is how one ought to play, and of course he expects reciprocity from me.
Am I required on my part to behave toward him according to his rules? But I do not want those rules.
Should I from the outset refuse to take the help he extends to me? That already does not seem reasonable to me. I cannot always control that help. For example, the most basic kind of help is simply not to attack me. If I see that the above-mentioned noble moralist is not attacking me when he has the opportunity, then naturally I will invest less in defending myself against him, and that is very significant help. To expect me to ignore during the game my assumption that he will not attack me seems to me very strange. And in general, to play in a way that is suboptimal from the game’s standpoint is also bad, because then there is no predictability.
By the way, what I did do was that many times, when I saw that someone was moralistic to an extreme, I wrote to him in the public chat clearly not to rely on me because “I’m not promising not to attack you.” The problem is that if he is a complete donkey, then for some reason such a clarification makes him attack me obsessively instead (which almost always causes both of us to go down to the abyss together). Besides, in most games the players are anonymous, so the chat is disabled.

[My decision at the time was to play only in order to win, with no other consideration, unless it has no effect on winning. But still, in the course of carrying out a particularly chilling and profitable betrayal against someone who had done me a favor, I would feel some kind of twinge in my back, and sometimes I would refrain from it and even return the favor, maybe even take a small risk in order to repay that favor—which is very frustrating to the other players if they do not hold by this morality, by the way, because a favor to one always means harm to another. So it turns out they lost because of moral principles and not because of pure in-game ability. And if, for example, three of us remain, and I am “loyal” to someone who did me a favor, then the third one almost certainly loses. In some sense, the morality there really degenerates the game. The games without morality—that is, games in which the alliance system changes almost every few turns depending only on the present situation and with no importance attached to the past, meaning that every player tries to maximize only his own chance of victory—are without a doubt much more interesting and sophisticated games, and only with players like that is it fun (for me) to play. From my point of view, adding external *constraints* to that is really poisoning the wells. By the way, the link got broken by an added space (not that anyone cares), and here is the correct one: https://www.chess.com/clubs/forum/view/is-it-a-game-without-morals ) ].