Southerners argued that slave labor was superior because

slaves worked in many industrial areas.
slaves actually enjoyed being property.
slaves and slaveholders depended on one another.
manumission brought shame to freed slaves.

Respuesta :

Southerners argued that slave labor was superior because slaves and slaveholders depended on one another.
They wanted to justify their need for slaves by saying that their symbiotic relationship is beneficial for both parties, when in fact, that wasn't the truth as they reaped far more benefits from this arrangement.