Actually, it is the FBI who 'believes' this stuff. No one said that it leads to or causes someone to turn into a serial killer. Rather, it is a predictor of that. Does everyone who tortures animals turn into one? No, but I'll bet that boys who set cats on fire, and so on, grow up to be the type of person I wouldn't like as a neighbor.
The FBI doesn't consider hunting to be abuse, to the best of my knowledge. Those of us who agree with that theory probably don't either.
The Humane Society, IMHO, is overzealous, and most likely controlled by those we'd consider too liberal or too left. But, that doesn't mean that they are wrong on everything. Myself, I donate at the local level, and volunteer as an animal rescue transporter now.
I think jail time was inappropriate. Rather, the dogs should not have been fed for several days, poked with sticks, the man smeared in animal fat, and his pups let in the cell. Cruel and unusual? Perhaps. Justice? I think so.