There's nothing wrong with wanting to be humane to animals, even ones that are ultimately killed for their meat (such as pigs). It's possible for an animal to live a perfectly content life and then be killed quickly and with as little pain as possible. And that's what a lot of people are campaigning for.
Reducing animal cruelty is not at odds with breeding livestock for food. We can have both. And to not support one because you want the other is disingenuous.
It does pose an ethical dilemma. Of course we can reduce the suffering of pigs. Yet we choose not to. We choose not to, because we like cheap pork. This presents us with an ethical dilemma if we actually think about the issue. Most people make a significant effort to avoid thinking about the issue, because they do not want to consider the ethical dilemma of "if I eat this bacon I cause suffering vs if I don't eat this bacon I won't taste bacon". Treating pigs humanely would require a massive increase in pork prices, which would reduce the amount of pork related pleasure people can have, thus a dilemma of its own. Treating pigs as we treat dogs would involve not killing them for food, totally removing the pork pleasure, and again poses a dilemma.