"In the beginning, there was the idea. The idea attracted others, like-minded. It flourished, and grew. Well, my friends, the idea has become the institution."
We participate in the most powerful of shared cultural ideas every day - like government and money. Some we fight against - but the very hallmark of an institution is that its detractors will try to define their alternative by comparing to the thing they don't like. To fight against the institution is to reinforce the belief in the institution. For example, consider the Satanic. What is a Satanist if not someone who still defines their whole world view on Christianity? Certainly, if you ever meet a Buddhist monk, you'll find that he does not define himself as struggling against the Christian God - so it is fair to say that Satanists are nothing more than devout believers in the concept of Christianity, though not its practices, and that everything they do only reinforces the idea, the institution, that they fight.
Another such struggle is 'racial discrimination.' Once the concept of race was introduced (and it is a fairly recent invention), it was rapidly used to combat the cultural shift in Europe away from slavery, and justify continued slavery under the guise that whereas before anyone of any country was fair game, now it would only be practiced on a clearly defined "other". Not that it was, and slavery continued under other names like "indentured servitude" as so many of the poor of the British Isles had their bonds sold by their owners and carted off to the colonies, whether or not it was officially called slavery anymore. (Political correctness is a new name for an old idea.) Nonetheless, western Europe moved away from the concept of slavery, as did its colonies, and the institution of slavery, the idea, has been abandoned so thoroughly that neither its supporters nor its opponents can make us believe in it as a place in civilized society.
Now that the justification that relied upon the concept of race is gone, so, too, may the concept of race slowly be relegated to the historical relics and museums. But there are very powerful institutions that have large amounts of political power and money, as well as ego, tied up in "fighting race" - they are the truest believers in racism, and determined to make the rest of us abide by both their shared concept and their interpretation of it.
Think on that, the next time you get called racist for judging someone not by the color of their skin, but by the content of their character.