Well, opinions vary. Things like this are an issue because there are a lot of vocal people on both sides of the fence.
I am, and likely always will be, one of those who agrees with the military not carrying it.
Indeed, I personally think people should not support this product with their money as well.
A lot of people disagree with me, but hey, differant opinions is part of what being in a free country is all about.
As long as the goverment does not actually make the game illegal in a general sense, I don't care.
The military has always had a lot more power than the civilian world to set policies, and that's something people going into the service are supposed to know. A lot of your civil liberties go away when you become property of the US goverment for however long.
Fanboyism is also something you need to consider with this. Shooters in general, as well as specific brands of shooter, have fanboys who will stand by them for any reason. While there are many people who are genuinely defending the "opposing force" thing due to believing in it, I think a good portion of the opposition are shooter fanatics who simply want to play the game and don't care as long as they get their "fix".
Sort of like how there are people who are supporting "Starcraft 2" and "Modern Warfare" despite the policies of the companies involved, and how they are being treated as consumers (gouged for money. Like with every shooter out there, there are people out there who look at the pretty graphics and the claimed gameplay innovations and go "OMG, this could redefine the entire genere" (even if it doesn't) and run out and buy it. When the shiny new game is shown off people tend to cease to care about all the other things that mattered to them before the game was actually about to be released. People will make all kinds of excuses like how they are supporting Treyarch and not Bobby Kotick, despite the fact that they are one and the same today, and no matter the label they are still going to get goughed on DLC.
In this case, I'm sure both shooter fanatics, and series specific "Medal Of Honor" fanatics would be wanting to support this game even if it say featured a taliban shooting range were abducted allied "infidel babies" were fired into the air like clay pigeons and gunned down in mid-air for points. Or if say if there was a whole single player campaign all about how wonderful Bin Ladin is, how evil America is and kill "The Great Satan" in the name of Islam.
None of those things are in this game, and at it's worst this was not that extreme, the point is that if the game HAD gone there, I think there would still be people defending it and saying all the same stuff, just so they could play their favorite genere/franchise.
See, I don't think gamers are actually literally addicts, but we do act like them at times, and I think we need to be a bit more assertive even if that means going without a game or three to make a point. There will always be more games. As long as it's our choice (and not one the goverment tries to make for us) I think gamers should really consider boycotting this game over the Taliban thing, and show that we do indeed draw a line somewhere on our own and have standards. It can be hard to argue we aren't being warped by violence and the like when someone can point a finger to this as an example of detachment from reality and a lack of moral standards. Just as I think gamers should not be purchsing "Modern Warfare: Black Ops" because of the business practices the company engages in, in this case not for morality but for our own benefit to tell the industry that there are limits to how far we're willing to be gouged for money.
Ahh well, thanks to those who read this far, apologies for the rambling, and like usual this is simply my opinion.