Friend, I've had as much as a quarter of a sim at times, and right now my group (which I'm contributing most of the land and tier for) is getting close to that again... and I still find the idea of banning people based on how much land they own or whether they've got a credit card offensive.
Great! From now on, I will determine what criteria is acceptable for you to ban people from your land, okay?
I'm going to make the kind assumption that you feel no moral superiority to me. Therefore, if you think I should not ban people from my land based on criteria you find offensive, then you can't ban people from your land based on criteria I find offensive. How's that sound?
So, let's say, for example, that I believe that any discrimination against age play is an act of pedophobia. And therefore, you will no longer be able to ban age play from your sim because I personally find your criteria for banning offensive. Nevermind that you own your land. What really matters is whether or not anyone is offended by your personal choice of who can and can not use your land, and how they use it.
See my point?
In other words, it's my land. I'll ban whoever I want on any criteria I want. You wouldn't want me telling you who you can and can not ban. Then don't do it to other land owners.