I mean, to be fair, Jackson was a 19th century Christian fanatic. He wasn't an advocate for some radically changed theocracy to take charge of the pre-war USA or the Civil War CSA. His fanaticism affected his personal behavior more than his political positions.

On the other hand… instead of Lee or Jackson, James Longstreet is right there.

Longstreet 'betrayed the cause' by daring to make peace with the fact that they lost the war and Black folk were citizens, that's basically treason to a Lost Causer. Jackson died before any such thing could theoretically happen, so he remains pure.