I think this is thinking about it backwards. The payment industry are discriminating here on the proportion of payments to porn sites which are fraudulent or di

I think this is thinking about it backwards. The payment industry are discriminating here on the proportion of payments to porn sites which are fraudulent or disputed, not the proportion of fraudulent or disputed charges which are to porn sites. It can be simultaneously true that the vast majority of fraudulent/disputed payments are not to porn sites and that a very large portion of payments to porn sites are fraudulent or disputed.