The Ohio guy had slept with A, B, and C, before he slept with D. If D knew nothing else, she could conclude that he must be attractive. After all, A, B, and C slept with him.
IIRC many of these altruism studies suggest that one thing people like is to believe themselves virtuous. So they undertake actions likely to reinforce that belief. Robin Hood could be sure it was right to steal, because he gave some of the money to the poor.
This is why people are so easy to persuade that whatever happens to benefit them is virtuous. They can then satisfy their self-righteousness and greed simultaneously. Who will object to a deal like that, if the only cost is to believe, whilst voting, that black is white, and 2 and 2 make 5.
Similarly, A is easily convinced that B is privileged in some way. A can then demand that something belonging to B should be given to A, and know that he is merely demanding justice. Even better if things are taken from B’s group and given to that of A, because A is now merely trying to help his fellow disadvantaged members of his group.
This is why every distinguishable group in the Western world is convinced that it is discriminated against.
How else to justify their greed?
