Frustrated? Please, I'm just vulgar.
Also, the emotions that we understand come from our brains, who are you to say other living life forms don't have other ways of expressing/understanding emotion? Isn't this the whole base of your argument for pigs? Like I said, they are still living and some plants have been proven to feel pain. If they can feel pain, why can't they interpret it in some way we haven't figured out yet? Ever tended a garden? Seen sick plants try to heal themselves?
Empathy for these animals in which they project human emotion and feelings on... That's what this comes down to. You cannot be empathetic with something that does not share our feelings, emotions, which as you said come from our brain. Sure they might have something similar, we might call it "happiness" but it isn't. It is literally impossible for a pig to have human feelings they are not human. You project because they have mammal eyes and that's it.
Again LIKE I SAID, I am not against treating our food sources well, I am against projecting our human traits on to animals then using that to justify things like "making sure they are happy". That's such non-sense.