I will agree that really shouldn't be his "power" since its basically using pawns to do his bidding and in reality that would mean Tobirama > Hashirama (Which is obviously not the case), but you're not interpreting the whole chapter incorrectly. That isn't what Itachi is referring to. Kabuto has had an identity crisis all his life and Orochimaru has been the person he's been closest to for the better portion of his life, so he tried (Without acknowledging it) to indirectly become a second Orochimaru. This is what Izanami was casted for. Until Kabuto accepts that he was trying to be exactly like Orochimaru, he will always be stuck in the loop. It has nothing to do with Edo Tensei being his power or not.
