I understand your point of view, but the provider also has to consider the users - especially those who spend a lot of money on the site. They are, after all, an important part of their business model.
A permanent ban would essentially only hit the users who spend a lot of money, since a gray or bronze user can easily create a new account on SC without loosing much. If it's just about harassing the model, every user type can do that on every platform with secondary accounts.
In CB, the user's status depends on the tokens spent in the last two weeks, so banning mistakes / misunderstandings are not such a big problem. In the worst case, the user simply creates a new account the next time he recharges tokens.
On SC, on the other hand, user status depends on total tokens spent, so users at the highest level will have invested over $10.000 to reach that point. Here, a new account is not a good alternative, since you would then have to constantly switch between accounts or spend $10.000 again to reach the old status (which comes with benefits like a free ultimate membership) with the new account.
At first, this sounds much worse for the models, but in reality, the unpleasant users on CB simply make new accounts all the time - since an account on CB does not represent a permanent value, but only reflects the consumption behavior of the last two weeks. Effectively, the situation is not noticeably better for the models on CB.
I even see a slight advantage for the models on SC, because the user can come back after a month, but is directly identifiable due to his unchanged name, while on CB he can disguise his past history much easier. On CB you never know for sure if the purple user is someone you have banned before under a different name. On SC, on the other hand, you can be relatively sure that a red user (who has thus spent $10,000 for this status) is not the idiot who annoyed you a month ago under a different name.
As I said, I understand that as a model you like to have a permanent ban, but I also see that the provider has to do a broader balancing of interests, especially when relying on such a long-term level system as SC. And I also think that a permanent ban on CB is only a perceived improvement, while annoying and harassing users simply keep coming back with new accounts.
