General Kelly's central points are not refuted by anyone on this thread.

In 1861 a Southerner's primary loyalty was to his state, not to the federal government, especially with respect to an issue such as slavery where the states were clearly in the right legally.  Dred Scott & the Constitution provided the legal basis for slavery which Lincoln and his allies simply ignored.

Moreover, tariffs, cultural differences, western lands, etc, provided other sources of contention which exacerbated the slavery issue.

General Lee was certainly much more honorable than Yanks such as Grant, Sheridan, and Sherman who pursued a policy of ruthless ethnic cleansing against innocent, defenseless women & children from Vicksburg to the Shenandoah to Darien to Atlanta and Charleston.

As was the case with their treatment of Plains Indians, Lincoln and his generals simply sought to exterminate Southerners to enable Northern hegemony.

By contrast, General Lee fought with honor, not by Total War.