The vast majority of people who get themselves into situations like this are hoarders. Hoarding is a real mental health issue.

Working with human societies, rescues and animal controls over the years, I have met a few of these people. I've been to their homes, confiscated their animals, talked with them. I can tell you, without fail, a hoarder sees the world through a different, skewed lens than you and I do.

They honestly and truly think they are helping. They truly love animals. They really think they are helping, saving, doing good. As incredibly difficult as it is for us to see these poor animals in these conditions, it is also impossible not to feel for the hoarder herself. She is truly doing the best she can, given her mental/emotional limitations, and she really thinks these animals would be worse off without her. It's a terribly sad situation for both the person and the animals.