Because you can get experience (and a clearance) work for 2 years, resign and come back to exactly the same job as a contractor at 2.5x the salary.
Or just make 2.5x without college debt and gov red tape?
Because it gives unexperienced and young people the status they think they seek - also connections which are inevitable - while they will be ultimately transformed into the people of the deep state. And hey, that's fine - even the deep state needs new people right ?