...and Gandalf suddenly had a brilliant idea of how to win the war.

[Kuruharan]

posted by Sophia:
Even though one could use them (or attempt to use them) in a way contrary to the original intent, the power of their maker is still resident in them, and his intentions were evil.

This is a point of consideration. I'm not sure that the West's use of orcs would really have been against the intent of their maker. The West would be using the orcs for the purposes of destruction, which was really all that Melkor was interested in.

Of course, this would have been against the interests of their current master but not against the original intent of their maker.