I don't think you understand how racism works. By even being part of it and supporting it in the least bit, by not just tolerating that it exists but by being a part of it is racist. It is a group that does not allow black people, jewish people, and possibly asian people to join just because they are of that race. It is IRRELEVANT what else he does and how nice he is or whatever. He is racist if he is part of that group. It is not up for debate. That's how it is. I'm sorry that you do not understand that but that's how racism works.
I have to agree, sorry. Becoming part of a group that enforces racist policies for the sake of a game of golf is not a good or nice or excusable thing to do in many people's books. He's supporting a racist organisation by being a part of it.