There’s a chapter on Jefferson’s Indian policy in my latest book, Thomas Jefferson–Revolutionary: A Radical’s Struggle to Remake America.
Jefferson favored assimilating the Indians into American culture, with its republican government, modern science, agricultural rather than hunter-gatherer basis, etc. He looked upon their stone-age cultures as backward and believed that becoming American would benefit both American citizens and Indians.
When people see the word “genocidal,” they think of mass murder. Another part of the definition has to do with eliminating a group’s culture. Since Jefferson wanted to assimilate Indians into American culture rather than leave them to their pre-Columbian ways, I suppose that fits. He certainly did not favor murder of Indians.
I haven’t read that part of Ivan’s book.