It's common to give contractors a bad wrap, and certainly some deserve it. But, many DOD contractors are ex-military persons, either retired, discharged, physically unable to remain in service, or simply choose to work "on the other side of the desk" (as they say).

Almost all the contractors I know were in the Air Force, Marines, Navy or Army for some period time. (It's usually very helpful as they still have the necessary clearances and don't need to be sponsored to get one.)