I would not call anti-tank missiles and explosively formed penetrator IED's 'light' weapons. You need to learn more a little bit more about what you cited before you use it in your argument. They are very poor examples when considering what is legal in this country.
Its been hammered into the ground at this point, but I disagree that IED's and Rocket Propelled grenades are the only thing the insurgency is using to cause problems for our industrialized force on the ground. Those weapons get a great deal of attention because of how effective they are but there have been plenty of times were an old fashioned firefight has broken out with M-16s going against Ak-47s.
And sometimes its the small arms which make it possible to acquire heaver explosives through the raiding of ammunition depots etc.
From my study of insurgency it is rarely the insurgency in and of itself that makes winning a war of that nature possible. Usually the insurgency has to gain enough momentum and credibility to encourage 3rd parties with more advanced weaponry to begin contributing (US in Afghanistan v USSR), but in the beginning it starts with a well armed group of politically motivated individuals.
Don't be an idiot like them, citing a piece of Hollywood fiction to even remotely back up your argument.
Again it was said highly in jest... maybe not worded correctly or executed well. Im not so stupid as to honestly cite a Hollywood creation as evidence for the success rate of insurgent movements.
I will say that the movie does present an idea which in this country we are not accustomed to thinking about. That is warfare on our ground. With the exception of a small island in Alaska during WWII no US soil has been occupied by an enemy force for roughly 200 years.