Heat84 don’t they have people who enlisted in the military that can do these jobs?
Having retired relatively recently after serving 26½ years in the Air Force, and having been involved with the management of contracted programs, I can address this.
This ain’t like the old military where uniformed personnel spent time peeling potatoes or emptying trash on KP duty, or cutting grass or mopping floors, or even doing many other technical but routine jobs that you may seen advertised.
Today’s uniformed warrior is trained and focused on Warfighter tasks. In the Air Force, for example, we don’t waste the time of an aircraft technician that we have spent a million dollars or more in training to do stuff that is better served by a contract services, or even a Civil Service, employee.
As already mentioned, non-uniform personnel provide continuity and reach-back support for the Warfighter.