Why is a pig fat? Because it's a pig.
It isn't "because" anything. It's who he is. Don't make excuses for him. He was born nasty and vulgar and will die the same way.
Why does poop smell bad? Because it's poop.
“Why does poop smell bad? Because it’s poop.”
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Having been born and raised on a tiny farm where we used draft animals I can tell you that some poop smells a LOT worse than some other poop. That from a horse that works hard all day without protest has a smell but while not exactly pleasant it does not knock you down. That from a pig that lies around in the shade, occasionally wallows in the mud and grunts and squeals in expectation of having food brought to it smells a lot worse.