It's about economics and the abuse of power in Washington DC. You know, the same crap we are dealing with now, from the same sources in Washington DC, enabled by the same rich "elites" in the Northeast.
From your link:
“It is not at all surprising, such being the character of the Government of the United States, that it should assume to possess power over all the institutions of the country. The agitations on the subject of slavery, are the natural results of the consolidation of the Government. Responsibility, follows power; and if the people of the North, have the power by Congress—”to promote the general welfare of the United States,” by any means they deem expedient—why should they not assail and overthrow the institution of slavery in the South?”
Kind of undercuts the false premise that there was nothing to fear about the future of slavery, doesn’t it?
“We prefer, however, our system of industry, by which labor and capital are identified in interest, and capital, therefore, protects labor—by which our population doubles every twenty years—by which starvation is unknown, and abundance crowns the land-by which order is preserved by an unpaid police, and many fertile regions of the world, where the white man cannot labor, are brought into usefulness by the labor of the African, and the whole world is blessed by our productions. All we demand of other peoples is, to be let alone, to work out our own high destinies. United together, and we must be the most independent, as we are among the most important of the nations of the world United together, and we require no other instrument to conquer peace, than our beneficent productions. United together, and we must be a great, free and prosperous people, whose renown must spread throughout the civilized world, and pass down, we trust, to the remotest ages. We ask you to join us, in forming a Confederacy of Slaveholding States.”
Is that another one of those pesky quotes that supports Yankee propaganda?