Is it moral to blindly follow orders?
No. It is imorral to not consider your own actions and their consequences. Blindly following orders is immoral in the same way that it would be immoral for a bridge building company to never test the materials they were being supplied with.
What constitutes a just war?
A war that does more good than harm for the world is just. For instance the invasions of Nazi Germany was just because the Nazis were not only subdugating their own people and committing genocide, but they would have continued waging war against everyone untill the planet was under their domination anyway. It would have been unjust to not wage war against them.
Say a policy maker wages an unjust war and orders mass amount of people to their deaths in order to kill mass amounts of other (otherwise innocent) people. Is this not morally comparable to genocide?
Not only is it morally comparible to genocide. It IS genocide.
Can you tell I'm bored?
Who isn't?
___________
To summarise my feelings on war. I don't care what the motivations for the war were. A just war is determined by its cost to the civillians in the warzone, the lives lost in persuing it, and the outcomes that result from it. Men who wage war should not have their motivations looked at. If an unjust war is caused by mistaken information then the leader needs to be punished just as much as waging it without the justification as punishment for not checking their information. However just because inaccurate information was the cause of the war does not mean that the war was necessarily unjust once you look at its results.