Why can't true hoarders do something as simple as this?

I’ve watched the show Hoarders but stopped since it was too depressing or something. But I’ve wondered why don’t they simply buy a bag of trash bags or leaf bags and throw away food-based garbage? I don’t mean knick knacks, photos, toys or books since I know they mean a lot to them but what about empty food cans, trash bags from the grocery store, molded bread and take out containers? Why do they let those stay on the floors? I want to add that I am no neat freak at all to say the least.