Yeah, people sometimes do apply double standards. But there's a big difference between shooting for food or protecting farm animals/humans from wild predators, and shooting a defenceless animal purely for sadistic pleasure.
people have been killing small fury thing for pleasure for centuries hell i'll bet you within the first month of .22/air rifles being first sold to the public a cat or dog was shot.
At least dog/bull/bear/**** fighting isn't common any more.