IMHO, the 150 baht fee is, indeed, a ripoff. Way out of line for charges made to Thais and aimed at foreigners. Of course, there is nothing original to these observations.

My solution is to us a Schwab Bank (USA) ATM card which repays me automatically for the 150 baht charge as well as any other charges and provides excellent exchange rates.

Sometimes I go to a Citibank branch in Bangkok where I have never been charged the 150 baht. By the way, don't use a Citi ATM card, even at a Citi branch in Bangkok as they add 3% onto foreign currency withdrawals.