"Didn’t men write the Bible?"

Absolutely. When you write a letter, do you write the letter, or does the pen? Obviously you do; the pen is merely the instrument you use. God used men as instruments to write His "letter" to humanity. They ranged from kings to common fishermen, but the 66 books of the Bible were all given by inspiration of God. Proof that this Book is supernatural can been seen with a quick study of its prophecies. See Psalm 119:105 footnote.