Honor killings would be a good example. Actually killing your sister to show the rest of the community how honorable you are.
It is an old tribal custom.
If he did not kill her, he would lose face, and the tribe would exiled him.
Plus, the female could never marry, her worth is nil, therefore with no support of the tribe she would starve and die. Spoiled goods as it were.
In the tribe everybody knows everybody else. Can't be hushed up.
Very harsh I know, but those were the rules and they did not change at all.
In some parts of the world it is still primitive mediveal times rule.
When they come to the more advanced parts of the world, the bring their mental baggage with them.
Can't get rid of the tribal mentality.