No, I have not lived as sheltered live (no pun intended). You seem to have made a point for my case. Once a sheltering system is removed, what you described on aboriginal lands and poverty stricken places will become more commonplace. There are no shelters on reserves. Some Bands have animal control but no pounds, is there an SPCA shelter in Bella Bella? Is there a shelter near you? How did the dog pack get there? What is their life like? Although living is good enough for you, (you said so if you were an animal) most want a better life for them?
Without a plan to prevent the type of cruelty you have described, should there be such a push to proceed. It is similar to some of the actions of the SPCA, the cart before the horse syndrome. To vigorously press a philosophy, but not offer solutions for obvious consequences will detract from your cause.
You would gain more support if your concept can appease all parties involved. In this case there is serious concern for those animals unlucky enough to land in the hands of irresponsible folks. Although one is too many, there are a great number of potential victims in your concept and that must be resolved first.
Most people do think their used pet will be fine in a shelter. Most people believed there pet is destined to die once in a shelter. A view also expressed by you and on the AAS website. So currently it is not guilt free to do so. If they do not experience guilt they are more likely to be a person that will simply release the animal anywhere but in their neighbourhood.