And no one believed the native Americans who said they used to hunt them. Then they didn't believe they actually saw them, only bones.

Then finally bones with tool marks were found. So now they don't believe native Americans hunted them, only scavenged dead bodies...

There were no living mammoths on mainland North America 5k years ago. 10kya, sure, but not 5kya.

Interestingly on multiple occasions enslaved Africans who saw the mammoth skeletal pieces identified them as a kind of elephant since they had seen similar back home. From Mark Catesby writing in 1731 on one such instance:

There is no Part of the Globe where the Signs of a Deluge more evidently appears than in many Parts of the Northern Continent of America, which, though I could illustrate in many Instances, let this one suffice. Mr. Woodward, at his Plantation in Virginia, above an Hundred Miles from the Sea, towards the Sources of Rappahannock River, in digging a Well about seventy Feet deep, to find a Spring, discovered at that Depth a Bed of the Glossopetrae, one of which was sent me.

All Parts of Virginia, at the Distance of Sixty Miles, or more, abound its Fossil Shells of various Kinds, which in Stratums lie imbedded a great Depth in the Earth, in the Banks of Rivers and other Places, among which are frequently found the Vertibras, and other Bones of Sea Animals.

At a Place in Carolina called Stono, was dug out of the Earth three or four Teeth of a large animal, which, by the concurring Opinion of all the Negroes, native Africans, that saw them, were the Grinders of an Elephant, and in my Opinion they could be no other; I having seen some of the like that are brought from Africa.

Also while on a vaguely related topic the last bison of North Carolina was shot in 1799… they once had a range much further east than people imagine today.