In case you wanted to mistakenly argue that Clippers owner Donald Sterling has had his First Amendment rights violated in the case of the NBA banning him for life for his remarks, please refer to this:
The First Amendment of the United States Constitution protects the right to freedom of religion and freedom of expression from government interference. Freedom of expression consists of the rights to freedom of speech, press, assembly and to petition the government for a redress of grievances, and the implied rights of association and belief.
The NBA is not the government. This is in no way a First Amendment issue -- nor are a lot of things commonly cited as First Amendment transgressions.