In A People’s History of the United States, what does Howard Zinn have to say about how Indians (indigenous peoples) and Blacks (both slaves and non-slaves) were treated by presidents such as Jefferson, Madison, and Jackson?

Howard Zinn, author of A People's History of the United States, served as a pilot during WWII, and his experience bombing France irrevocably tainted his opinion of war and politics. He depicts the Native Americans as hospitable, progressive, and noble. His book's first chapter, "Columbus, the Indians, and Human Progress," vividly recounts Columbus's landing on the shore of the Americas, welcomed by the Arawak Native Americans. Columbus himself, in a letter to the royal court of Madrid, wrote that the natives were "so naive and so free with their possessions that no one who has not witnessed them would believe it. When you ask for something they have, they never say no. To the contrary, they offer to share with anyone" (ch. 1). He describes the Iroquois as quasi-communists ("land was owned in common and worked in common") and holding women in high relatively high regard ("families were matrilineal," and "when a woman wanted a divorce, she set her husband's things outside the door," ch. 2, "Drawing the Color Line").
Africans were first enslaved by the Portuguese (fifty years before Columbus), and Zinn remarks that slavery in the US was convenient, practical, and precedented. He also notes that, unlike the Indians (who were on their native soil) and Europeans (who were surrounded by their native culture), Africans were helpless, which made enslaving them easier. Thomas Jefferson (president from 1801 to 1809), in addition to authoring the Declaration of Independence, infamously owned hundreds of slaves during his lifetime. He also (equally infamously) had a relationship with a slave woman of mixed race. Zinn notes that Jefferson's attitude toward slavery is ambivalent; on one hand, he owned hundreds of slaves until his death, and on the other, he wrote a paragraph of the Declaration of Independence accusing the King of England of "suppressing every legislative attempt to prohibit or to restrain this execrable commerce" (ch. 3, "Tyranny Is Tyrrany"). This chapter was later removed by the Continental Congress, composed as the Congress was of so many willful slaveholders. Zinn also recounts that one black mathematician, Benjamin Banneker, wrote to Jefferson, asserting the humanity and equality of black people and imploring Jefferson to rid himself of prejudice against them. Zinn concludes that

Jefferson tried his best, as an enlightened, thoughtful individual might. But the structure of American society, the power of the cotton plantation, the slave trade, the politics of unity between northern and southern elites, and the long culture of race prejudice in the colonies, as well as his own weaknesses-that combination of practical need and ideological fixation-kept Jefferson a slaveowner throughout his life. (Ch. 5, "A Kind of Revolution")

James Madison saw slavery as a profitable enterprise: "James Madison (president from 1809 to 1817) told a British visitor shortly after the American Revolution that he could make $257 on every Negro in a year, and spend only $12 or $13 on his keep" ch. 2). Madison also, Zinn notes, hailed from a wealthy slaveholding plantation.
Zinn introduces Jackson as "a land speculator, merchant, slave trader, and the most aggressive enemy of the Indians in early American history" (ch. 7, "As Long as Grass Grows or Water Runs"). To illustrate this claim, Zinn cites a massacre by Jackson of a village of 250 men, women, and children of the Creek Indians at Fort Mims (in 1813). A year later, at the Battle of Horseshoe Bend, Jackson killed over 800 Creeks with the aid of the Cherokees (who were promised favor and friendship by Jackson). Jackson routinely destroyed villages that refused to accede to whites' claims to the land in what is now Florida. He waged the Seminole War (in 1818) against the Indians in Florida, on the pretext that these lands afforded sanctuary to escaped slaves (ch. 7, "Slavery without Submission, Emancipation without Freedom"). While Zinn acknowledges that there were "atrocities on both sides," these select occurrences illustrate Jackson's overall exploitation of the Indians. While Zinn presents Madison as an unapologetic slaveholder, he was, in a sense, a product of his time, and (according to Zinn) eager at the prospect of the financial gain that slavery afforded, Jefferson's relations with blacks demonstrated a perpetual internal conflict toward slavery as an institution. According to Zinn (and popular opinion), Jackson was perhaps the bitterest enemy of the Indians of all US presidents to the present day.