It's like the difference between Sam's Club and a typical grocer. The grocer offers services to the public, Sam's Club does not. It is members only. And it can have any requirements it pleases for membership. It doesn't have any racial exclusivity policies, but that would be well within their rights if they did. (For instance, country clubs have often had racial exclusivity clauses, even after the civil rights act.) Sam's Club is not a company for the public.

When you need consideration for membership, there really is just no way you can claim that to be non-private. That includes Patreon, it's private. It's their rules. Full stop. It's like adwords, if you want to use it, you have to start giving Google more consideration. Normally to use the public parts of Google, you don't need to give any consideration at all. (Of course, Google takes the tracking information from you anyway with their public facing services, but they don't ask you to actively give them any consideration.)