Slavery was started under the British, so they would be a good one to add to your poll. However, I do believe that all of our Foundering Fathers share some blame for not addressing the problem when this country was created. After the creation of this country the South shares blame for creating a society built around slavery and the North shares blame for looking the other way and profiting because of it.
The Founders did address slavery in the Federal Convention. South Carolina and Georgia threatened to not approve the Constitution if they didn't have slavery.
"It seemed now to be pretty well understood that the real difference of interests lay, not between the large & small but between the N. & Southn. States. The institution of slavery & its consequences formed the line of discrimination." [James Madison, Speech in the Federal Convention Opposing Equal Representation in the Senate, 14 Jul 1787]
"Some for such a qualification of the power, with an exemption of exports and slaves, others for an exemption of exports only. The result is seen in the Constitution. S. Carolina & Georgia were inflexible on the point of the slaves." [James Madison to Thomas Jefferson, 24 Oct 1787]
"The southern states would not have entered into the union of America, without the temporary permission of that trade [slave trade]. And if they were excluded from the union, the consequences might be dreadful to them and to us. We are not in a worse situation than before. That traffic is prohibited by our laws, and we may continue the prohibition. ... The gentlemen from South Carolina and Georgia argued in this manner: 'We have now liberty to import this species of property, and much of the property now possessed, has been purchased, or otherwise acquired, in contemplation of improving it by the assistance of imported slaves. What would be the consequence of hindering us from it? The slaves of Virginia would rise in value, and we would be obliged to go to your markets.' I need not expatiate on this subject. Great as the evil is, a dismemberment of the union would be worse. If those states should disunite from the other states, for not indulging them in the temporary continuance of this traffic, they might solicit and obtain aid from foreign powers." [James Madison, Speech in the Virginia Ratifying Convention on the Slave Trade Clause, 17 Jun 1788]
"The Petitions on the subject of Slavery have employed more than a week, and are still before a Committee of the whole. The Gentlemen from S. Carolina & Georgia are intemperate beyond all example and even all decorum. They are not content with palliating slavery as a deep-rooted abuse, but plead for the lawfulness of the African trade itself--nor with protesting agst. the object of the Memorials, but lavish the most virulent language on the authors of them. If this folly did not reproach the public councils, it ought to excite no regret in the patrons of Humanity & freedom." [James Madison to Benjamin Rush, 20 Mar 1790]
So they addressed slavery. They just didn't come to the solution we wish they would have come to.