As many have said, we call him 'Zero' because he's a cipher. An enigma. A phantom. A myth.
No one remembers him well enough to comment favorably, because he never left a wake in life. Never left an impression. Never touched anyone's life in a memorable way. He passed like a shadow - gone like a puff of smoke on the wind.
He was a blank canvas on which the deep left could paint the image of the perfect candidate. The man is a complete fabrication.
Well said.