Well.. it IS kind of funny and yes, I actually saw a non-gaming journalist have a similar reaction to the multiplayer mode while I was playing it at the last Sony event I attended (he's not into "scary stuff"). So, on THAT front, it's a brilliant ad.
On the other hand (Devil's Advocate cap on), I can see this ad being used by the anti-gaming crowd that thinks EA is clearly targeting children under 18 with Dead Space 2 and any other M-rated games they publish, which may force EA to deal with "news" outlets merely looking to rake them over the coals unfairly (and once again, if you remember the stupid controversy around Mass Effect two years ago). These folks have less of a sense of humor than a jar of pickles (and about eight times as much vinegar in their veins), so giving them this "gift" as more anti-game ammo might backfire a little too much. So, on THAT front, the ad is a giant "WTF were they thinking?"
Either way, the game will sell, as there's not really such a thing as "bad" publicity these days...