So, up front, I think CSM is silly to imply there's any issue here.
Moving on though, there's a reason this type of imagery gets such a rise out of the US: we have zero institutional memory of widespread destruction on US soil, especially from an external force. Our Eastern Seaboard hasn't been an active battlefield since the 1880's, and the last time the aggressor was a foreigner was during the War of 1812. With isolated incidents like Pearl Harbor (Hawaii, btw, wasn't even a US State at the time), the original WTC bombings, and 9/11/2001, we're just not accustomed to it. Our institutional experience of "fellow citizens dying" is primarily of them dying "over there": Vietnam, Korea, Somalia, Iraq, Afghanistan, the Western theater, the Pacific theater. You don't need to invoke "American Exceptionalism" to understand why people have strong feelings about this; you just need it to explain our chosen method of coping with those feelings.
Now on to my real question: what scenario has IW possibly come up with that makes DC look like it does in that trailer? Fallout 3 makes sense: the entire world is in ruins. DC is just a single microcosm of destruction. Judging from the trailer, it looks like all-out warfare, a la the fall of Berlin! What military scenario results in that? It certainly isn't accomplished by a team of guys in street-clothes and bulletproof vests (seen elsewhere in the trailer). You'd need another military (or coalition) of similar size to the US military, along with the capacity for launching a long-range invasion (significant naval resources, supply-chain management, etc). It is exactly the kind of war that American generals have been fantasizing about since the end of WWII, spending way too much money preparing for (thank you, Cold War), and that analysts say is absolutely the least likely thing to happen. Nearly all major world powers are way more interested in economic conquests than military ones.
THAT's what fascinated me about that trailer.