It's spectacular hypocrisy to say that you can't base a game in a present-day war but you can base it in 'old' ones. Did I imagine Battlefield: Vietnam, for example? There were still plenty of Vietnam veterans about when that was released, just as there are still a few WWII veterans. And if we're trying to make moral judgements here, it's important not to forget that the average Wehrmacht stubble-hopper had nothing at all to do with the excesses of the Nazis in general, which is why at the end of the war we didn't end up with war crimes tribunals lasting into the next century. A lot of the guys we cheerfully gun down in Medal of Honour or whatever were conscripts who got the nice choice of joining the Army, or getting shot by their 'own side'.
Where was the moral outcry against Blackhawk Down? It's based solidly on real events in a theatre of war that's still active and topical, and as much as it tried to keep to the facts, it was an entertainment, guns, explosions and bravado movie. Indeed Call of Duty 4 not only drops you into something that looks a hell of a lot like Iraq, it nukes the place to add a bit of spice to the proceedings.
The people getting offended by 6 Days are almost certainly not the servicemen who were involved there. One of the earliest games I remember, Gunship, was a simulation of flying the AH64 Apache designed by a US Army Major who had done it, and wanted other people to see what it was like, and we know Fallujah vets were involved in the design of 6 days. No, the people complaining are the usual suspects who complain about everything from Action Man dolls and GI Joe comics, to the A-team. They're the people who complain if someone gets shot in a movie or game and doesn't show the effects of it realistically because it 'hides the consequences of violence'- and then in the next breath, complain about any more realistic depiction because it 'glamourises violence'. Over here in the UK, their most recent manifestation has been amongst teachers trying to ban the Forces from making school visits in case they 'brainwash' kids into wanting to join up- as well as those who whined that Sky TV's series following Ross Kemp embedded in Afghanistan was 'exploiting' the troops for entertainment purposes. The same troops who now regard Mr Kemp as practically one of their own and who were desperate that the real story of what they were doing should come out.
There's no reason for the games industry to let itself continue to be pushed into this ridiculous 'just for kids' ghetto in this day and age, with so many players in the 20-40 age bracket. We're adults, and we have our own minds, thank you very much. If you want the objectionable face of gaming, it's far more likely to be found in one of Rockstar's controversy-baiting crime sims than in something like 6 days.