The answer should be obvious: Expected utility.

In practical terms, this means weighting according to severity, because the quantity of people affected is very close to equal. So we focus on the worst forms of oppression first, and then work our way up towards milder forms.

This in turn means that we should be focusing on genital mutilation and voting rights. (And things like Elevatorgate, for those of you who follow the atheist blogosphere, should obviously be on a far back burner.)