Properly speaking he was bron in Austria Hungary where he was part of the German speaking minority in Bohemia. He may have taken Milena as his tutor to allow him to phase into the Czech Civil Service, so he might continue at his day job, at the Workmen's Compensation, but . . . and then again, where are the works of Lakser-Schiller, or Paul Celan, both Jews and both major German poets deposited. Then too, lasker Schiller spent her last days in Jeruesalem, and Celan lived most of his life in Bssarabia, which changed hands three times in the last century, so . . . You figure it out!
from the article: National Library: Kafka writings belong in Israel