Only Sadists Keep Snakes, or So Sayeth the Internet
In the course of my work with Pets Unlimited, I spend a fair amount of time doing research, both on and off the clock, in order to learn more about the animals I care for, and in order to address some pretty specific problems. Because a large number of my sources ultimately wind up being blogs operated by breeders, I usually wind up learning a fair amount about what non-keepers think about the keepers of various things. The most hated of all, of course, are snake-keepers.
Now, I myself don't keep snakes, recreationally, anyway. I might, if I can ever get the Girl Worth Fighting For over her unfounded fear of the things. As pets go, snakes are high affection for low maintainance (though, as with any pet, you get what you pay for). Why the hate on for snake keepers?
It has to do a lot with their food. Snakes are obligate carnivores, and for the majority of pet species, the meat of choice is rodent. Snakes, of course, are notorious for needing to be fed live food, which is a half-truism I'll address in the moment. Because you're feeding live things to other live things, the whole practice is seen as being cruel and unusual.
Now, let's set aside for the moment that live food sometimes wins, to the injury or death of the snake in question, and focus on some alternatives. You could, in theory, feed a snake nothing but frozen-thawed. First you'd have to train the snake to accept it, and then you'd have to come up with a way to compensate for the lack of nutrition in the frozen foods available.
Not to mention, a frozen rat is still a rat.
Now, I've said it before but it bears repeating: if it were up to each of us to hunt, kill, prepare, and then eat our own meat, most of us would be lacto-ovo vegetarians. I've known people who turn up their nose at fishing (being a fish keeper, I find my nearly-strictly seafood summer diet amusing, to say the least). If you have a pet, and your pet is not a bird or an obligate herbavore, somewhere, someone killed an animal to feed it. That goes for all dogs, cats, reptiles, and yes, even fish. The fact that your food comes in nice, brightly-coloured packages absolves you of nothing.
For the record, when feeding live, once you're no longer dealing with infant animals, it becomes necessary to pre-kill the prey item immediately before feeding. I would say that that level of responsibility - the need to personally take the life of one creature to sustain the life of another, is the ultimate level of discipline in the pet hobby.