Well wasn't morgoth just the child of the Gods? As is all the powerful players in Middle Earth.
After all wasn't Middle Earth created basically by the children of the Gods singing...and those that would form the elves song beautifully or such, and Malkor song with the most power...and so he's technically not evil when you think about it.
All that evil is in LotR is "dominance", forcing your will over others.
Morgoth was the one who could do this, and he did, and Sauron took his place in a smaller way afterwards yah?