When used as an insult, it is a metaphor in the sense that when herding animals, the owner hires working class men to crack a whip to tend his herd. The herders or cowboys have no real authority other than to crack the whip and do what their boss says - the man with the real power. When used as a slur, 'craking the whip' means to run ones mouth, complain, rant, bitch and moan, blog, etc because as a schlub, that is all he can do; essentially a wimp.
The only thing worse than a cracker is a cracker with a badge, they think the own the place.
No one is fuckin better than anyone they are equal, until your actions or reputation lowers your social status and respect, of course.