It's like encoding and enabling chattel slavery is striking a blow for Liberty!
I suspect it is more like you are ignorant of history.
Daniel Webster testifies to the fact that the Founding Fathers intended for slavery to perish.
Daniel Webster, THE CONSTITUTION AND THE UNION, March 7, 1850, (In the Senate)
http://www.senate.gov/artandhistory/history/resources/pdf/Webster7th.pdf
Page 271
"And now, let us consider, sir, for a moment, what was the state of sentiment, North and South, in regard to slavery at the time this Constitution was adopted. A remarkable change has taken place since, but what did the wise and great men of all parts of the country then think of slavery? In what estimation did they hold it in 1787, when this Constitution was adopted? Now it will be found, sir, if we will carry ourselves by historical research back to that day, and ascertain men's opinions by authentic records still existing among us, that there was no great diversity of opinion between the North and the South upon the subject of slavery; and it will be found that both parts of the country held it equally an evil, a moral and political evil. It will not be found, that either at the North or at the South, there was though there was some, invective against slavery as inhuman and cruel. The great ground of objection to it was political; that it weakened the social fabric; that, taking the place of free labor, society was less strong, and labor was less productive; and, therefore, we find, from all the eminent men of the time, the clearest expression of their opinion that slavery was an evil. They ascribed its existence here, not without truth, and not without some acerbity of temper and force of language, to the injurious policy of the mother country, who, to favor the navigator, had entailed these evils upon the colonies. I need hardly refer, sir, to the publications of the day. They are matters of history on the record. The eminent men, the most eminent men, and nearly all the conspicuous politicians of the South, held the same sentiments, that slavery was an "evil," a "blight," a "blast," a "mildew," a "scourge," and a "curse." There are no terms of reprobation of slavery so vehement in the North at that day as in the South. The North was not so much excited against it as the South, and the reason is, I suppose, that there was much less at the North; and the people did not see, or think they saw, the evils so prominently as they were seen, or thought to be seen, at the South. Then, sir, when this Constitution was framed, this was the light in which the convention viewed it..."
Page 273
"...there was an expectation that on the ceasing of the importation of slaves from Africa, slavery would begin to run out. That was hoped and expected."