As someone else mentioned, pigs are smarter than dogs, and they're social like dogs, with individual personalities. So if you're against harming, mistreating or torturing a dog... why would you not be against harming, mistreating or torturing a pig? I think most meat-eaters would say that they are against the mistreatment of pigs. But make no mistake, when you buy bacon, ham, etc, you are paying for the abuse and torture of pigs. See the second video below for a glimpse of factory farms, which is where 98% of pork comes from.
As for the question of the thread… the animal industries only care about making money, so even with animal welfare laws, they still don't care and they'll still exploit and mistreat the animals. But even if they are treated a little bit nicer during their short life, they still end up dying a violent painful death, there's no such thing as "humane slaughter." Once I realized that, I realized that it's not about trying to do the wrong thing in a nicer way… But just don't participate at all with it. Vote with your pocketbook and if you care about animals, don't pay for others to harm them, simple as that. Going vegan was the second best decision I ever made in my life, and the only regret I have is not doing it years sooner!
Check out his proud smile at the end of this clip: