Neely is a hostile, South-bashing wonk who plays the wonk game of "let's pile up the paper, and whoever piles up the most paper wins, and everyone else has to shut up".
He's playing to back up Foner and McPherson's play on driving the South into the sea historiographically.
That pile of paper is called evidence, and you're playing the sothron game of "let's ignore our own faults and call everyone who brings them up biased and tell them to shut up." Have you won yet?