Why would Jack need a body double if he’s a nobody unless he expects that people will want to assassinate him at some point?
What company would bother committing murder and/or genocide on dangerous areas for the sake of good? What could he possibly gain by killing bandit camps for the sake of good?
I’ll let you think of the answer for the first question, but here’s the answer to the second one: Money. He says that he wants to kill the bandits on Pandora to clean up the place for those already living there, but from a business standpoint, it makes no sense. Corporations usually don’t do charity cleanup unless they can profit in some way, like money or good publicity. The whole point of Jack wanting to cleanse Pandora is because he wants to re-purpose the land for building upper middle-class and rich communities to profit off of. And with a giant-ass laser at his fingertips, what would stop him from killing the poorer native Pandora civilians to re-purpose their land for the rich as well? It’s genocide for self-profit. That’s why he has the laser, that’s why he wants to kill Pandoran camps; Self-profit. Not the good in his heart.
I think the beginning scene here is a good visual of what I’m thinking here:
Also see the lyrics for the Dead Kennedys song Kill the Poor.