I dont know of any snakes that eat the domesticated rats/mice that we as keepers feed them either. African soft fur rats and striped mice are natural for BPs, and so are some birds. Do you/would you feed your snakes birds then?
Humanely euthanized and fed off I can see it happening. Me personally, I couldnt. Just like I cant feed rabbits to giants. But are people wrong for it? IMO, no.