As I said, relationship has true significance only when it is a process of self-revelation, when it is revealing oneself in the very action of relationship. But most of us do not want to be revealed in relationship.
We are all members of the same flawed species. Putting our moral vision into practice means imposing our will on others. The human lust for power and esteem, coupled with its vulnerability to self-deception and self-righteousness, makes that an invitation to a calamity, all the worse when the power is directed at a goal as quixotic as eradicating human self-interest.
A human being in relation with another has very limited control over what happens in that relationship. He is a part of a two-person unit, and the control which any part can have over any whole is strictly limited.