I don't recollect that Tolkien stated this. This is a quote from the good reverend who wrote this article. If I'm wrong, please tell me what writing of Tolkien's this quote is from.
I remember reading his bio more than two decades ago, and if my memory serves me correctly, Tolkien hated war. He lost his best friend in WWI. Trench warfare. Nasty stuff. Much of his experience during the war influenced his writing.