That misunderstands free speech. Free speech means the government cannot punish individuals for speaking. It doesn’t mean private organizations have to give individuals a platform, and has nothing to do with how consumers choose to spend their money.
Here’s the thing — there is virtually no difference between the logic of “White supremacy” and the fundamentals of racism. In order to be racist — you have to be surrendered to the logic that the very people you deplore are somehow beneath your station. There is no way that you can feel “supreme” without owning some measure of superiority.