My daughter goes to the University of Virginia, founded by Thomas Jefferson.
The school is currently having some discussion of his slave ownership and it's legacy. While I cannot speak about the other president's you named, if you check Wikipedia, you can see that in Jefferson's case it is not that cut and dried:
"Throughout his life, the third President of the United States, Thomas Jefferson, owned hundreds of African-American slaves, and his position on slavery has been studied and debated by his biographers and by scholars of slavery. Starting in 1767 at age 21, Jefferson inherited 5,000 acres of land and 52 slaves by his father's will. In 1768, Jefferson began construction of his Monticello plantation. Through his marriage to Martha Wayles in 1772 and inheritance from his father-in-law John Wayles, in 1773 Jefferson inherited two plantations and 135 slaves. By 1776, Jefferson was one of the largest planters in Virginia. However, the value of his property (land and slaves) was increasingly offset by his growing debts, which made it very difficult to free his slaves and thereby lose them as assets.
In his writings on American grievances justifying the Revolution, he attacked the British for sponsoring the slave trade to the colonies. In 1778, with Jefferson's leadership, slave importation was banned in Virginia, one of the first jurisdictions worldwide to do so. Jefferson was a lifelong advocate of ending the trade and as president led the effort to criminalize the international slave trade that passed Congress and he signed on March 2, 1807, a few weeks before the British did the same.
In 1779, as a practical solution to end slavery, Jefferson supported gradual emancipation, training, and colonization of African-American slaves rather than unconditional manumission, believing that releasing unprepared slaves with no place to go and no means to support themselves would only bring them misfortune. In 1784, Jefferson proposed federal legislation banning slavery in the New Territories of the North and South after 1800, which failed to pass Congress by one vote. In his Notes on the State of Virginia, published in 1785, Jefferson expressed the beliefs that slavery corrupted both masters and slaves alike, supported colonization of freed slaves, suspected that African-Americans were inferior in intelligence, and that emancipating large numbers of slaves made slave uprisings more likely. In 1794 and 1796, Jefferson manumitted by deed two of his male slaves; they had been trained and were qualified to hold employment.
Historians now accept that after the death of his wife Martha, Jefferson had a long-term relationship with her half-sister, Sally Hemings, a slave at Monticello. Jefferson allowed two of Sally Hemings's surviving four children to "escape", the other two he freed through his will after his death. The children were the only family to gain freedom from Monticello. In 1824, Jefferson proposed a national plan to end slavery by the federal government purchasing African-American slave children for $12.50, raising and training them in occupations of freemen, and sending them to the country of Santo Domingo. In his will, Jefferson freed three other male slaves, all older men who had worked for him for decades. In 1827, the remaining 130 slaves at Monticello were sold to pay the debts of Jefferson's estate."
