Do you know why George Lovett Kingsland Morris was so invested in Native American Art? Was he himself Native American?
No, he himself was not Native American at all. He was born into an old and affluent Anglo-American family.
He was interested in reinterpreting Native American art and craft as abstract "fine" art because he was looking for "authentic" American source material. Abstraction in American art was influenced by slightly earlier European movements like Cubism, and American artists were trying to put a homegrown stamp on the movement.
Ironically, Morris was part of a group known as the "Park Avenue Cubists."