People who maliciously physically or mentally abuse animals need help. It's absolutely appalling. I've never first-hand witnessed the worst sorts, but I'm a sucker for programs about animal rescues. They always make me cry.
However, one of the biggest beasts is just simply a total lack of information out there. Lack of information about where animals come from and about proper husbandry. Sometimes horror cases are simply the result of a well-intentioned owner who doesn't know any better. Of course it's up to the individual to do research before you buy an animal, but it sickens me how plainly some breeders and pet shops are willing to sell an animal to someone just to make a cheap buck-- not telling them about special care requirements, or outright lying.
I bought Lady from a terrible pet shop (I never would under normal circumstances, but something just clicked...) there was at least 16 budgies in a 12x12x12 display case. The staff saw people walking by and doing things like yelling into the bars or raking their hands across the bars and terrifying the poor birds but did nothing-- they in fact, tried to talk THOSE PEOPLE into BUYING the birds.
I'm sure we all know that you never see an article or new snippet about what complex animals parrots are and how much research someone should do before even considering buying one, but I know first-hand that almost no-one knows how complex of animals say, rabbits are. They can be free roam animals, they require hay and proper pellets and fresh veggies daily. They can be litter trained and learn tricks, and need mental stimulation and lots of room to exercise (in a large cage if they are kept in one, and daily time outside of the cage of at least 2 hours). They can live up to 12 years. Yet, the average person thinks they sit in a tiny cage and eat a seed mix, living just 3 or 4 years. It all just makes me sad....