Housecats cannot feed themselves. They learn hunting from their moms as kittens, and if their moms are kibble fed housecats then they themselves won't have the skills to pass on. Are you saying you go out and bring them home half-dead mice which you then kill and eat in front of them so they get the idea, and then bring them progressively less and less dead mice until eventually you bring them one fully alive and let them kill it? Even as a graduate of my cat's "teach a monkey to hunt in only 30 days" training program (¥), I can't imagine how any civilized ape could possibly know enough about feline hunting skills to pass those skills on to a kitten.
Raising a kitten and then releasing it as an adult is akin to putting out a bird feeder all summer and then quitting filling it upon the first snow fall.
Dogs have been bred over many millenia to not only accept their human masters, but to truly love their role. Dogs are pack animals and even in the wild, they choose a leader to follow. It's the role they're most comfortable in. The cruelest thing you can do to a pack animal is turn it out on its own. That's what wolves do to individuals they see as inferior and unworthy of the pack, and it's the ultimate rejection. Lone dogs not only tend to starve to death, but they do it with the misery of having been rejected from the only family they've ever known. And you would have me believe me you do this as a kindness?
Whether or not you approve of the past 30,000 years of dog breeding is irrelevant. It's done, and now domestic dogs not only want, but need humans for their livelihood. It brings them genuine happiness to be with us, to have our love and approval. The free food, padded bed, and flea powder ain't so bad either. Look at packs of wild dogs with their protruding ribs and miserable sad eyes if you want see what happens when we abandon them.
Besides, any cat caregiver will tell you who's really the boss. I let my cats out whenever they want. Do you think I force them to come in when they get chilly, fill their bellies with food they didn't have to chase down before curling up in their luxurious Special Spot, somehow managing with their 10 lbs of body to occupy my entire queen size bed?? They beg for my attention and demand access to my lap, especially if I'm trying to do homework. I have had lost cats run into my house when the door was open and make themselves at home. You presumably find your home quite comforting when it's pouring rain out. Is it such a stretch that your cats prefer this, as well? I assure you, my cats are anything but captive prisoners.
(¥) Yep. My cat took me through the whole routine that her mom took her through. First she brought me dead mice and left them for me to eat. I politely disposed of them when she wasn't looking, but she thought I ate them. Next they started coming back less and less dead. She'd show me how to kill them. Eventually she brought me one that was maimed and bleeding all over, but still very much alive. She watched me euthanize it by dropping a log on it, quick and painless. I was traumatized, to put it mildly. That was my final exam. I passed, was certified capable of looking after myself by my doting pet, and she never brought me another mouse again. True story.
“As I am sure any cat owner will be able to tell you,
someone else putting you in a box is entirely different
from getting into a box yourself.” —bisexualbaker