Why they were not called that by the Jews in Jerusalem?

Jews in Jerusalem did not refer to themselves as "Christians" because the term was primarily associated with followers of Jesus who believed him to be the Messiah, a concept that diverged from traditional Jewish expectations of the Messiah. Early Jewish followers of Jesus considered themselves part of Judaism, viewing their beliefs as a continuation rather than a departure from Jewish teachings. Additionally, the term "Christian" emerged later in Antioch and was not used by the original Jewish followers of Jesus in Jerusalem.