‘Right’ and ‘wrong’ are ultimately biological notions. It is wrong to poison drinking water, because doing so kills and injures, and it is right to provide people with clean drinking water because doing so has the opposite effect.
Obviously views vary as to what is health-conducive, this being why some people may regard promiscuity as wrong and others may view it as right.
Also, people lie about their own views on these matters for reasons of self-interest. So, for example, slave-owners probably concocted rationalizations for the existence of slavery.
But after differences in what people want are taken into account, there is surprisingly little disagreement about moral issues, the reason being that, as stated, morality is tied in such obvious ways to human health and welfare.