How is feeding pre-killed rodents barbaric? Last time I checked when I sit down to my dinner table my food is quite dead. When you pre-kill a rodent you have the ability to do so in the quickest/most humane way possible. Using CO2 gas the rodents fall asleep and don't wake back up. No pain, no panic just sleep. Whereas feeding live isn't going to be painless or necessarily quick either. Not to mention the fact that a live rodent has the potential to hurt the snake during the feeding process.
Ball Pythons evolved to hunt/eat small mammals and to some extent birds. They mainly use their heat pits and sense of smell to hunt. Insects and lizards aren't even going to show up on the menu to them. As has been stated numerous times in this thread already, if you don't want to feed rodents don't get a ball python, it's just that simple. Don't put your wants in front of the snakes needs.