Sure why not. Keeping an animal lockeed up in a small place is cruel.
We do that to people, its called prison. Its not considered a pleasent thing.
If you're saying that you essentially object to keeping animals as pets in general, that's cool. I can see that point of view, even if I don't agree with it. Won't argue it. I just don't like it when ppl think it's somehow more cruel for one pet type than another because it seems a bit hypocritical. Dogs, after all, are kept in large "cages" called a backyard - sometimes even only a part of the backyard (a "dog run") then taken out for walks once a day (like prisoners being given an hour of yard time per day, to use your anology). So not like they're running free, either, so to speak.

Our cat was desperate to be outside for the couple of weeks she had to be confined indoors. She really wasn't very happy with the idea at all.
Cats have varying personalities, of course. Generally speaking, if you raise a cat always indoors, they aren't going to miss what they never had. I've had cats where I can open the backdoor and they'll ignore it all day...they sniff at the doorway occasionally and walk away - windows are nothing more than "TV".
On the other hand, if a cat has been feral/stray or raised to be allowed to come and go as they please, they will have varying degrees of response to being suddenly told they have to be indoor only cats. I've had some that wouldn't tolerate it (I found other homes for them) and some who preferred it (once indoors they never seemed to want to go outside again). So I'd never say ALL cats are "best" kept indoors...only that being outdoors is not a requirement to healthy/entertained living. I also would never say that people who like their cats outdoors are bad pet owners. Just preference and circumstance.
Besides, keeping cats indoors helps keep them out of trouble. It decreases the chances they'll pick up ticks, get hurt by neighborhood animals, or get struck by a car.
+1
As a kid, my cats were indoor/outdoor cats. Lost 1 to a car, had 1 lose half her tail somehow (caught in a fence maybe?) and so on. If I lived on 20 country acres without traffic, maybe....anyway, I've kept 'em inside ever since I started living on my own. No fleas, no ticks, worms, no chemicals/drugs needed, no muddy-cat baths, no death by misadventure is my preference.
