My friend and I used to live together for some time. He ended up with a cat that was supposed to be put to sleep, because the shelter said they see no hope the cat is ever going to be happy and not constantly anxious and stressed and just plain unhappy.
Now, we managed to make him okay, but it took YEARS with us just concentrating on him in a home environment. I totally understand why they didn't have the time and resources to do it, when at times even we thought it was hopeless.

So in a way, I don't want no kill shelters, but in other ways, nobody would have taken in this cat if it wasn't for my friend's absolute lunatic Borderline Personality Disorder ex doing it. She also mistreated it, that's how we ended up with the cat. It's not a typical "I saw this cat and needed to have it" story. It also took a long time of a situation when you have a pet in your living space that thinks you are probably Satan, which is disheartening.