Humm... he's complaining that the contractors are charging 170k for a given job, yet paying the actual person doing said job about 80k (less than the national average and less than a government employed equivalent). In the poster's experience, the contractor isn't actually providing anything, the government pays the utilities, the office space and provides the equipment. So that extra 90k is for... uh... to make sure that the contracted employees fill out their timesheets, and... uh... that's it.
He's not saying he wants to eliminate that 306 billion, just that a lot of fat could be trimmed if contractors that only provide employees would be eliminated and the people hired directly by the government.
Unfortunately, that won't happen because governments like to say "we've cut 50 000 government positions! yay us!" but at the same time, they hire 50 000 contractors for twice the cost (obviously, that last part is left out from their news briefs).