The term pig in this song has nothing at all to do with the police.
The song is sung by the 'power(s) that be' about the minions(people) who basically walk around with their head up their ass, who do as they're told and are easily fooled.
The easiest way to explain it is, if you imagine Kim Jong Il (leader of North Korea) as the butcher and the ordinary North Koreans as pigs.
Pud
