Not a comparable situation. Spencer didn't do anything to disrupt the gym. The equivalent on the forum would be if someone on was minding their own business posting about Blockland and I banned them because of a completely unrelated post they made on another forum. Legal or not, it's morally wrong to use your power as a business owner to attempt to police all aspects of your customer's lives.
Well there's the whole thing about what constitutes as "disrupting the gym". He's an advocate for all kinds of tribal anti-social ideas apparently, if people are disgusted by his presence to the point to cause a scene then isn't that disrupting the gym? I don't see how that's an attempt by the gym to control Spencer's personal life. All they have control over is making Spencer not come to their gym.
What about that Mattnett dude whose key you de-activated because he made some handicapped claims about you and the game on some Yahoo questions submission? Isn't that kind of controlly? Speak ill of me and I'll take away
your ability to interact with this online community you may or may not care about.
Personally I think that a business owner should be able to serve whoever they want. If you don't want to bake a cake for a couple whose lifestyle goes against your religion, you shouldn't have to. Neither should you be enforced to allow a person in your gym with views you dislike. If there is a problem of discrimination which is having a significant negative impact on certain individuals, there should be legislation that helps them out.