They're stupid if they're just saying something everyone already knows. It'd be like saying "the US government assassinates civilians with unmanned airborne vehicles" or something.
It's borderline. Even if all the people in the know know it, it wasn't accepted as fact when it was't convenient. Or rather, politicians could pretend it wasn't real / a problem.
Well, perhaps stupid in that calling them conspiracy theories is a mark of ignornace, when they'd be better termed as uncontested and easily supported public facts, or something.
So to be clear, when someone calls an easily supported public fact a "conspiracy theory" to dismiss it, "stupid" should be applied to them, not to the so-called conspiracy theory.
The comment was tongue in cheek. Of course they do this.