You don't have to be a U.S. citizen to be tried by the U.S. Government for war crimes. (See: Nuremberg Trials)
"Jurisdiction thereof" refers to the legal status at the time of birth and not getting arrested for a crime later in life.
For example, was his father subject to be drafted by the U.S. Government at the time of his birth as was a similar U.S. citizen or legal resident alien? Or were both of his parents foreign citizens?
In the late 19th Century and early 20th Century, American Indians were considered members of "Indian nations". That is why they were not considered U.S. citizens simply by being born on U.S. soil inspite of the XIV Amendment.
That did not change until the passage of the 1924 Indian Citizenship Act
"Be it enacted . . ., That all non-citizen Indians born within the territorial limits of the United States be, and they are hereby, declared to be citizens of the United States: Provided, That the granting of such citizenship shall not in any manner impair or otherwise affect the right of any Indian to tribal or other property. Approved, June 2, I924. "
If your interpretation of the XIV Amendment were correct, there would have been no need to pass the 1924 Indian Citizenship Act.