That every single human on earth, sadists excluded, sincerely believes that their innate beliefs are what is actually good. Every point of view, even if not supported by facts, or even if there is no real underlying reason to believe something, other than personal choice, is a valid one. Some people never had a chance to be anything other than what you or anyone else may claim as ignorant.

While certain opinions that place one human as superior to another are certainly very narrow-minded, the person who believes such is not innately evil to themselves. The belief is a product of the environment that they grew up in. Acceptance of other humans as they are, should be the most taught policy to our children. While it is very hard for some to accept that a person could possibly discriminate against another person for something they cannot control, the fact remains, this "less enlightened" person is a human just like you. Just because you are willing to accept others for who they are does not mean that you should not accept those who can't. Some people are just incapable of accepting others for who they are, it is, while unfortunate, still true.

This is applicable to nearly everyone. This is easiest to explain with an example. There are people who simply will never be able to accept a homosexual person for who they are, and that is certainly unfortunate. But it also means that those who understand that someone who is homosexual is just another human being, must accept the homophobe for who they are, even though a homophobe doesn't give this courtesy to others, it should be given to them none the less.

This is not a cry to stop pro-equality movements, it is simply an explanation that people who do or believe things that you could never imagine doing or believing, are also people who, for whatever reason, believe differently than you, but I suppose if this were widely believed that equality itself wouldn't even be an issue