I realize I've laid out a slippery slope. That's why I was hesitant. The strongest case is for banning organized, large-scale animal cruelty done for depraved enjoyment. But I don't think we should prosecute people because we don't like, for example, that they use electric shock collars to keep their dogs from running off.
I'd summarize my position as: 1) animal interests for their own sake are not a legitimate end of government coercion, and 2) the moral character of the people is a legitimate end, but we should be very hesitant to use coercion for social engineering.