That too is something you wish to believe because if you didn't, you'd have to confront some unpleasant facts.
Another except from the same source really cuts through the obfuscation:
“ WHO PAYS THE DUTIES
The grievance, however, which is most insisted upon by writers and speakers of the Cotton States is, that the heavy duties imposed by the United States bear with undue severity upon them ; many do not hesitate to assert that they pay all, or nearly all, the revenue of our government derived from duties on foreign goods. That this is believed, is evinced by the reiteration of the statement. It is sometimes supported by the argument, that as the return for Southern cotton is wholly in foreign commodities, the duty imposed upon them is virtually a tax upon the Southern cotton. This position is specious enough to mislead those who do not trouble themselves to think or inquire. Those who do, easily detect the fallacy. The consumer of imported goods must pay not only the foreign cost, but the duties and all intervening profits and charges ; the producers of cotton pay duties, under our system, only upon such goods as they consume…
…By analyzing the entire expenditure of the five Cotton States of South Carolina, Georgia, Florida, Alabama, and Mississippi, we may ascertain, if not with certainty, yet with a fair approximation, what proportion of their income goes to the support of the government….
…The cotton crop of these five States was, according to the census of 1850, eighty per cent, of the whole product of the United States, and if that proportion is maintained, may be stated at three millions two hundred thousand bales, yielding, at forty dollars per bale, the vast sum of $128,000.000…
…A careful examination warrants us in stating the cost of making cotton and delivering it at the port of shipment, or in the markets of the United States, at not less, on the average of all places and soils in the five Cotton States, than $24 per bale. The cost of placing 3,200,000 bales in the ports of the South or markets of the North is not less than $76,800,000.
This sum taken from $128,000,000, the price supposed to be realized, leaves for the producers a surplus of $51,200,000. If we take from this surplus the money used by the planters for purposes where money is indispensable — as, for taxes, payment of interest, purchase of negros,—say one-half the surplus, or $25,600,000, which is only a small fraction over $12 for each white person, this would leave the same amount for the purchase of foreign goods and for the purchase of productions of Northern States….
…This exhibit forbids the idea that the people of the five States pay as much or more than their proper proportion of the duties upon foreign goods.“