Sorry, Tam. You have this all wrong. Anyone can choose to do business with anyone they want for any reason, as long as they do not discriminate against a protected class. Even if the reason is for retaliation. Now, if that person is a "preacher" (as you stated), elderly, handicapped, etc., they can CLAIM that you discriminated against them for that reason. Then, it is a matter for the courts to decide whether there was inappropriate discrimination. That is a different discussion that what we are having. Or, maybe not? Are you saying that Alsop is in a protected class that prevents Musk from selling to him for that specific reason?
So, when is retaliation illegal? I'll give you an example. When an employee discovers that there is a safety violation and speaks publicly about it, and then the employer fires that employee, THAT is illegal. No such contract exsists between Musk and Alsop. Besides, if Alsop was an employee, and openly spoke poorly about Tesla, that is sufficient reason for termination, again, unless Alsop was reporting a concern about safety or impropriety. He was not. He was just being nasty.