Past the edit window, but I had another thought:
I think that because indoor/outdoor/barn becomes such a contentious question, it muddies the waters.
So I'm going to give a different example of an "Is it really better to preserve the cat's life if this will be its living situation?" question.
My county's animal shelter is no-kill. They work hard to solicit donations and adopt cats out, but it's an economically depressed area where people don't tend to put a lot of effort into animal ownership. As a result, their adoption rate is such that at any given time they have quite a few animals they've been housing for 2+ years at a stretch.
The shelter isn't horrible, but it's honestly pretty grim. The cats spend most of their time in cages, and there isn't a lot of time for volunteers to spend with them.
Is no-kill really working here?
I'm not a cat, but if it were me I would honestly prefer a quick painless death to living for years in one of those cages. And I think that standpoint has to be considered, too.
Now, not to say those are the only options. The best
option would be for the shelter to be able to do things differently, to raise more money and rely more on foster homes. (Which they're working on.) When we're looking at the present situation, though... it's an issue.
When we consider whether no-kill is viable, we have to look at the quality of life for the cats themselves, not just the numbers. Hopefully this is a better example of that than something so open to different interpretations as barn cat life.