Sigh.
Lal, you insist on taking that quote out of context.
Allow me to remind you of this, which may have been overlooked: I have read that Tolkien understood evil to be negative, as in the absence of good. Thus, evil is flawed good. This can be seen in various place throughout Tolkien's writings, in which he uses the prefix, 'un-' to describe a thing, such as 'un-light'.
As to the verse, I would be interested what the original Hebrew says, for my New King James version has Isaiah 45:7 this way:
I form the light and create darkness,
I make peace and create calamity;
I, the LORD, do all these things.
Just to add oil to the fire.... :P .... Amos 3:6 says:
If a trumpet is blown in a city,
will not the people be afraid?
If there is calamity in a city,
will not the LORD have done it?
It is also interesting that Tolkien says that there is no humanly acceptable answer to the problem of evil if one posits a wholly good God (or Eru), which I still insist
The Silmarillion does, in spite of how it can be taken out of context.