I dont understand the logic. You are saying its ok to breed a rat for food, but not a cat. To be honest, both have an equal right to life, regardless of the purposed of its breeding. The only reason you dont think cats should be fed to snakes, is because society has taught you to think that this should be a domesticated animal, and should not be used as food. I bet in indonesia, china, and other pacific islands where it is common place to eat both cat and dog, they would have no problem feeding a kitten to a snake.
dont blame the snake for eating the cat
dont blame the owner for feeding the cat to the snake
blame society for brainwashing you into justifying the death of an animal because its not cute and cuddly. Kill the ugly eh?
Im not saying I would do it myself. But I find it hard to believe that cuter things havent been eaten in the wild.