You’re missing the point. It’s one and the same. Slaves were valuable economic assets whose value was diminishing as industrialization intensified.

The slavers wanted to conquer the west with slaves to stay relevant. Slavery was about wealth and control, in losing control of poor white people. The northern industrialists wanted cotton. Abolitionists saw the moral disgrace of slavery as an evil. Lincoln was more moderate and prioritized the nation.

The “states rights” bullshit was always bullshit. But then “get shot to keep rich aristocrats rich” isn’t a compelling battle cry. Conversely, the poor Irish and others participating in draft riots saw abolition as competition from the one strata of society lower then them.

Hence, the noble abstract goals of “preserving the union” and “protection our sacred rights” are front and center.