It sounds like you're conflating legal arguments with moral ones.
You're saying animals lack rights so it's morally okay to enslave/make use of them?
I'd argue it's much baser than that. Animals have feelings and often feel very bad when kept in enslaved conditions. Since humans can understand the pain they inflict on enslaved animals, then it's wrong of us to continue enslaving them when we have alternatives that are just as healthy for us, if not more healthy.
I would also say your assumption that pigs do not comprehend their actions and cannot choose between alternatives is false.
I'd argue it's much baser than that. Animals have feelings and often feel very bad when kept in enslaved conditions. Since humans can understand the pain they inflict on enslaved animals, then it's wrong of us to continue enslaving them when we have alternatives that are just as healthy for us, if not more healthy.
I would also say your assumption that pigs do not comprehend their actions and cannot choose between alternatives is false.