If you go with this line of reasoning, whoever put him in that position should also be fired, and their boss should be fired for putting someone in charge who made such a poor decision in the first place.
The person that should be fired is always the person who has responsibility for the amount of budget represented by the loss.
e.g. No intern that needs permission to get a box of pencils from the supply closet should ever be fired for putting a mistake into production that costs a company $100,000. If a company loses $100,000 on a mistake, you look to the person in the hierarchy who manages budgets of that size. It's their job to make sure the safeguards are in place to prevent losses like that.
In government it's difficult but not impossible to put a dollar value on losses like this. In this case, whoever was in charge of that network, and could request budget to build safeguards (whether software or training) against such mishaps, was ultimately responsible. Firing the intern is just shit rolling downhill.
Firing the intern means that the story you just spun to your boss about how this all occurred won't be contradicted by the intern and you might not get fired.
Only part of that makes sense. The person putting an intern in such a position of control should be reprimanded, but it wouldn't make much sense for the next level higher because there isn't a blatant mistake. Hiring someone that turns out to make a mistake isn't as blatant as giving an intern the power to shut down a mission critical system.
