the constitution limits the power of the State; the NBA is a private organization. the NBA is thus not constrained by the US Constitution. furthermore, sterling voluntarily agreed to be bound by the NBA Constitution; no one forced him to. finally, while sterling has a right to his noxious, racist views, he does not have a “right” to own an NBA franchise; that is a privilege
finally, it is not clear that sterling was unaware he was being recorded. apparently his mistress was employed as his “archivist” and sterling knew she was recording him, according to some reports.
Exactly. And if some other organization you belong to, say your health club, tries to fine you for your speech, you'd tell them to pound sand.
Difference is, this privelege is so lucrative that Sterling will do whatever they say.
So if he is forced to sell, he should be fully compensated at fair market value for his property.