Race has no biological basis. Race is assigned based on biological features (hair, skin, etc), but biological features do not uniquely map to a race. Academics know this. Or at least they should. However, if you are an academic who believes in race, and would like to use this belief to promote the notion that white people are superior, you can make a living off of it.
Enter Charles Murray, the author of the racist and scientifically debunked text, Bell Curve. He was recently invited to speak at Middlebury College, and despite espousing nonsense, his place on the stage at an institution of higher learning was justified under "the freedom of speech." If Murray were there to tell his story of UFO sightings, describe his theory of a flat Earth, or to discuss his attempts to interbreed various types of unicorns, this defense would not be available to him. But because he has staked his career on dabbling in America's age-old dark art of racecraft, and because his ideas add a scientific patina to established beliefs in the superiority of white people, universities nationwide have a seat and a microphone reserved for him. (Just as similar offers are open for Jeff Sessions, Mel Gibson, our president...)
Now let's turn to the case of Megan Rapinoe and the U.S. Women's Soccer team. Ms. Rapinoe refused to stand during the national anthem in protest against America's racist double standards, in solidarity with Black NFL players who were doing the same. If such double standards did not exist, she would be able to rely on the freedom of speech to express herself and draw attention to injustice in a non-disruptive, yet powerfully symbolic manner. However, the team has decided to institute a new rule that requires players to stand during the anthem.
This should not be surprising given our racist societal structure; but it will be unsettling to anyone who believes that racism is but a small, unfortunate blemish on an otherwise pure fabric of freedom for all. Protesting the double standard is not protected under our society's notion of "freedom of speech," thereby highlighting and reinforcing the double standard itself. If it were needed to prove the point, this is yet further evidence that the freedom of speech is actually the freedom to discriminate. Without that freedom, our society's racial order would be far more difficult to maintain.