My next point:
As we all know after the conversation with the "Catalyst"-child, it IS the Citadel. It governs the reapers and invented the "solution" called "harvest".
Because it IS the citadel, it can control anything what happens there. The council, the population, C-sec... all we know about the Citadel could be developed with the (silent) approval of the Catalyst.
Why did it send -respectively call - the Sovereign and Saren to attack the Citadel - so to speak to attack itself? Just to open that "gate" for the rest of the reapers? If it is powerful "beyond any comprehension" of all organic lifeforms, why does it need an indoctrinated spectre and the Sovereign to make itself up for it's creations?
Which explanation did I forget or not understand?