Do you mean all of the writings that included him? The Dead Sea scrolls they found even disparaged his name. Regardless of my desire to believe he didn’t exist, it is unlikely that people made him up at that time, then had random people talk and write about him.
By your standards, Alexander the Great did not exist, Socrates was a dream, and Siddartha Guatama was a fable.
That’s just not how it works.