Because like the pigs, we have become fat, lazy and conditioned. Never underestimate the power of brainwashing. Given enough time, it is like a stream flowing over a rock. No matter how strong the rock or how small the constant stream, unless the rock is removed from the stream, it will eventually wear down and become diminished until it is but an insignificant pebble. Unlike rocks, we have arms and legs and, in theory, minds and free will.
Why do you suppose the wild pigs are conditioned and fattened up? NOT because those who planned and executed the trap and continued to put out the feed want to be nice to pigs.