If you have a problem with someone's methods of care, you should give your opinion! You may change their mind about something. Or, it could be a complete waste of breath. Either way, it's always better to try.
Like Ontario_herper said, feeding an adult once a month isn't really a problem. I feed my BPs when they are hungry. With one, my 6 year old WC rescue, it's every 5-7 days. With the other one, it's about every 10-12 days. They both know when they want to eat, so I leave it up to them.
I don't agree with feeding live..but you should have said something to the guy! You could have said something along the lines of "you wouldn't have to TOUCH the rat if it were dead, either. You could just pick it up with tongs." This man might not have even know that there was another way to feed (besides live).