As per the papers cited, Jonathan Edwards dismissed critics of slavery by saying that all Americans were "partakers" of slavery. Even if not owning slaves, even if objecting to the practice, they "may have their slaves at next step."

He had grown up with slaves and owned slaves. All social status in America was keyed into slave-owning. All clerical work, all political work, was reliant on it.

But you say it wasn't necessary to the economy. LOL.