This is the sad kind of suicide food. This poor, poor, pitiful pig! This poor, stupid, trusting pig. Set adrift on the cruel seas, he thinks he's pleasure boating! Little does he know (or have the capacity to grasp) that he has been cast out, to be weakened by thirst and tenderized by the sun's pounding mallets.
It never even occurred to him to ask. Fork and tongs still held at the ready, he wanders farther and farther toward his doom, the one thought still rattling around his head like a pea in a jar: "Sure was nice of the fellas to invite me to their barbecue!"
He might have known, somewhere in there, that it would end like this. (Or with him dead one way or another, at any rate.) But he doesn't mind.
Addendum: It might be instructive—or, hell, it might at least kill a couple minutes—to compare the Big D's pig with the Landry's Seafood crustacean. They're sitting in their inner tubes in the same pose, feet dangling in the water. They're both at ease. But the lobster/crawfish/whatever is clearly more in-the-know. He's got a captain's hat, for Pete's sake! He's in charge of his own bloody destiny, whereas the pig is too darn dumb to steer clear of his.