Cats were bred, and evolved, from wild animals, outside animals. We wanted them to stay close, to us, as rodent control and as companions.
It is only within the past 50 years or so, that parts of society decided that cats should only be inside someones home, ignoring evolution and the desires of other groups of our society..
Yet, in our society, because of cat haters and actually cat lovers who insist cats be inside, over 99% of cats brought into almost all local, tax supported, "shelters" are killed, and it has become the norm.
Of that, over 90% are healthy, or have very minor conditions, or usually, in the allotted time (usually 24-48 hours) do not show themselves as being friendly and playful or easily adopted, so are simply killed...
While most of us think that is absolutely horrendous, most of us turn our heads and ignore it, which, in itself, is horrendous!
If your cat was caught in a trap and brought to the local "shelter" with different people there, kept in a tiny cage, would it be friendly and considered adoptable within 24 hours? If not, it would most likely be killed too.
There are actually several groups, and sub cultures, in our society that want cats around, as they have been forever, and don't necessarily want them indoors. Is it right to tell them they can't keep a cat like this, or if they do they very likely would see it killed if brought to the local "shelter".