I don't think anyone is saying that it isn't suspicious. They are just saying, "not so fast" on saying it is a chemical weapons plant.
The way I see it. They found a facility that was camoflaged and guarded. So it obviously has some strategic military value to the Iraqis. Second, there was something about it that made the people who found it think it had some chemical capacity so that would probably rule out an ammo dump.
At the very least then, what we might have here is a facility for making something like solid rocket fuel.