I didn't say anything about tax dodging. Kasikorn don't copy a passport as they say use their atm which doesn't copy a passport and gives them the 220 baht fee they want.
staff would spend time serving someone making an international withdrawal when they could be serving customers that make money for the bank. And if too many people were making international withdrawals they might have to.take on extra staff.
Some UK atms decline many Thai atm cards. UK ATMs can charge fees for cards issued outside the UK and EEA and some operators do.
In Thailand, some ATMs charge Thai cards issued in other provinces a fee between 10, 20 or 30 baht charge.