>When we think sexist legislation (say, women can't vote) is wrong, we usually think it's wrong for everyone and that the people/places that do it should stop.
Yes, but we ourselves think it -- e.g. we extend our ethics to everybody.
Others think such legislation is ethical, and consider us unethical, corrupt, etc (e.g. Saudi Arabia).
Pluralism is unstoppable, but so is our instinct to create/defend/assemble a common ethic.