Yawn.
Do you think our Founding Fathers were ok with slavery because it wasn't outlawed by the Constitution and some also owned slaves themselves?
Since at the Constitutional Convention, the Founding Fathers tabled the issue of slavery in general, and the slave trade in specific (giving the new Congress the power to ban the slave trade in 20 years)---fearing that it might derail the entire process by alienating those representatives from the southern states, whose economies depended on slavery---I'd wager that yes, it's fairly logical to assume that some Founding Fathers---namely, perhaps, those from the southern states---were "okay" with slavery. They might have been "okay" with it more as an issue of necessity and practicality vice morality, but the fact that the entire Convention could have been derailed over the issue of the slave trade is proof positive that some were "for" maintaining it, and by extension, the institution of slavery itself.
That's the same logical methodology the left uses for justifying their anti-war position. We, as a nation, are not in favor of losing the war on terror. However, when certain groups (liberals) poll the populace, they put the question as one of "dissatisfaction" with the progress of the war. Just as America can't be said to be "ok" with losing the war on terror based on this assumption, there was a majority against slavery at our founding. The issue was tabled because otherwise the southern states wouldn't have signed on to the Constitution. Highlighting these individuals as representative of the whole is hardly an honest disagreement.