I agree with one slight yet very important modification. The right to free association includes the right to not associate. The principle stands on it's own merits/reason. There is no requirement for a secondary reason. Thus a business can chose whether to associate for no reason. All too often people rationalize a secondary reason as cause to trump the primary reason. Thereby subverting the premise.
Example: "why do you (not you personally) not allow blacks or females or this that or some other criteria not to enter your business?" Answer: "there is no reason. It's my right to refuse access as much as it is my right to grant access." As soon as the proprietor gives a reason collectivists assume they have the right to use that reason against the proprietor to force the proprietor to do what the authoritarian collectivist demands. It's wrong, yet that is how it all too often happens. Thus the reason for my calling it a very important distinction.