How are these arguments not the same statement, just worded differently? Either way, your hand is touching their food. In fact, using the same logic, wouldn't picking them up with your hand to move to a separate enclosure and then feed be more likely to create a food-hand association than just feeding without handling? As stated by others, work based off of what you and your BP need, not some "I heard from a guy who heard from a guy..." that one or two people out of hundreds say they have experienced.