I'm not going to cut and paste (or type out) the whole forward but more than half of it talks about this claim in considerable detail. It's not new. Tolkien say

I'm not going to cut and paste (or type out) the whole forward but more than half of it talks about this claim in considerable detail. It's not new. Tolkien says: - He dislikes allegory in all its forms - The relationship between any author's experiences and his writing are amazingly complex. - The story is meant to provide a good long tale that would move, delight and surprise readers. It is not meant to have a deeper meaning by intention. - Parallels between WWII and LoTR simply don't work. - The key parts of the story are by far the oldest. - The old miller had a black beard and his name was not Sandyman (his final dig). He was far more influenced by his classical background and philology than current affairs.