I always wonder about this too. Can't seem to figure out how the sentence scale is measured and applied by the courts sometimes.
We had a woman living close to here that was arrested for cruelty to animals a while back. She had a number of horses that were very neglected. Granted, no excuse at all for that kind of thing. The horses were confiscated and she was tried, convicted and sentenced to TEN years in jail. All in less than a months time.
On the other side, we have a jail full of REALLY bad guys in jail for what seems like forever. Then, when they finally do get through the courts, the sentences are far less than abusing animals. Guess PIA would think that is a good thing, but I doubt most people would.