You're asking credit card companies to spend money to audit every single transaction, sort them based on charges generated inside the US, verify it's a gambling company, and then tax the transaction and pay the IRS the amount for each individual. So if I go gamble the credit card company has to know what the transaction is for....forget it because its so unrealistic anyway. Credit card companies are not going to spend millions and hire a army of coder's trying to keep up with this in their accounting system not even mentioning the millions lost in fraud from these businesses.