It makes sense to me, what in this post are you refuting. And if you justify a response with cited material, be assured there are much more evidence that supports these facts. Oh and common sense...an animal likes being in a cage because it's proto species used a den while birthing.
There are plenty of sources supporting the idea of "crating" dogs - heck, I could provide the links. It is an effective way to reduce the natural behaviors of a dog beyond the extensive domestication that has already been done over centuries. Since people no longer generally live on farms or homes with open spaces, it's a way to "speed up" that domestication to adapt to "modern" lifestyles, by conditioning it to being confined to a small box/cage for extended periods of time. Particularly the idea of a dog living inside the same dwelling as humans and not a dog house is a very modern one.
Just like you can condition any sentient animal (including the higher intelligence animals, like apes and yes, even humans) to "accept" confinement (or, more accurately, stop showing outward signs of protest), "crating" does. Not long ago, someone wouldn't dream of owning a dog in, say, a city. Now, people demand to live wherever they want and still keep an animal that is meant to be running around all day outdoors.
That said, none of the supposed justifications generally given for it for it have any basis in science whatsoever. Wild animals that seek the protection of "dens" (on
3 sides) do so for just that reason - protection, so they don't have to worry about being ambushed by predators. And even in wolves, it's only for mothers with young pups, as you point out. Wolves sleep outside in the open. They are the alpha animals in virtually all environments they live in (hence the terms we use in common parlance - "top dog", "alpha dog", etc).
I don't have a real problem with it, people can do what they want - but the notion that it is "good" for the dog is a lie people tell themselves, and has no basis in reality. It's really simple why, as I said, even some place like the Humane Society supports it - one, because it prevents them from being left unattended outside where there is a greater chance they can get loose and create a problem which leads to...two, because it makes the dog behavior more palatable to humans so the humans don't act aggressively/abusively to dogs, or the owners themselves from doing so when the dog "misbehaves" when left unattended indoors.
That's the irony to it - it's not directly about the welfare of the dog whatsoever, it's about reducing the abuse they receive from humans.
[Note, this an interesting, and essential, difference between dogs and cats - even aside from the fact that small cats are not alpha to begin with, cats
do seek out confined spaces (though again, with 3 sides, not 4). It's because we intentionally domesticated dogs, originally for agricultural and transportation work. The notion of dogs as simple pets and not tools is not nearly as old as one would think. Cats, on the other hand, pretty much domesticated themselves - while dogs were bred intentionally to domesticate their behavioral repertoire, the only reason people have ever intentionally bred cats is for physical features that make them more attractive to people.]
