No, what we are worried about is that if this kind of fantasy DLC is successful we will start seeing it in other flagship games developed by Paradox, and then it will be taking away from dev time that could have been spent on mechanics/gameplay DLC that contains with it at least a grain of historical plausibility.
This isn't just about one DLC, this is about where Paradox is heading with the DLC it offers as a company. If this DLC is successful and nobody protests, than what prevents them from creating "Alien Invasion" DLC for HoI and other ridiculous scenarios.
You have your right to say that you find this kind of DLC justified, but many of us disagree, and the only way we can make Paradox understand that is by showing our displeasure here on the forums and then voting with our wallets when it comes out.