You need to have followed this disaster from the beginning to see that this current government was not the culprit.  Scheers defence of his former government's actions are indeed very weak. Under Canadian law Harper should have repatriated him much sooner and the financial damages would have been mitigated. 
Finally, Trudeau is correct a Canadian is a Canadian. There is also serious doubt that Khadr was the one who threw that grenade based on the forced confession the Americans imposed on him through torture. They have been discredited for that.