The notion of everyone being equal has to do with the equality under the rule of law, and nothing else. There can be no other categories of measures in that regard precisely because you cannot perform any meaningful measures across several different dimensions of differences. For instance, would you be able to make a meaningful measure of who is underprivileged the most - an orphan billionare who is not likeable by anyone in his close circle of "friends" or a poor family of 5 who regularly get invited to family dinners in their community? What are the standards?