I find it more funny how they managed to trace it back to the Collective so quickly. It's not as if they beamed the planet into Collective space with a big sign saying 'STOLEN PLANET!' or turned up with an army to do so, they quietly dispatched a small group, which could be passed off easily as Infandus if they were caught (Or even Goa'uld infected individuals' into chaos which would likely make them harder to spot, and then the planet disappears about 15 minutes later and the New Romans instantly try to declare war on a Nation they barely know anything about (I assume the Asari were able to tell them the difference between Collective warships and the ones attacking the planet, as the latter were massive pyramids in a frame. If not, the Asari are blind xD)
So, to lay it out
They know nothing about the Collective, but are somehow able to detect what is theres and what isn't in the midst of Chaos (Duck suggested there were millions of soldiers in his last post) and trace it back to the Collective ignoring the Elephant in the room (This is a little like finding a hundred thousand Chinese soldiers with a single Russian fighting among them, who could be anything from a merc to a gangster to someone who moved to China, and thus saying it's all the Russians fault, declaring war on Russia and ignoring that China was the one who invaded) after they see technology they know nothing about (And thus couldn't possibly know whether it's Collective or not, it's a wormhole not a space ship) and then declaring war on a nation they know nothing about on what is essentially a guess... GG xD
By nothing I mean very little. I doubt the Asari were able to fill the Empire in with everything they know about the Collective in such a short time.