Hmm, I was going to jump in and say just about what you did here, only with a lot less detail...
But then I thought, well, the kid's probably right, in a sense. That is: could a bunch of civilian couch potatoes (or gym rats, what difference does it make?) defeat the US military, in a military conflict? Of course not.
But- if it were not a military conflict, but a sustained occupation/police action, could those civilians wreak nearly as much havok as (non-military) Iraqis have? Why not? Doesn't require a whole lot training/sophistication/technology to foment disorder and fuck shit up.
Of course, it will never come to that in the US (sorry, would-be Wolverines!) because it would be Bad for Business. So really, there's no point wanking about it at all.