Why do Kazakhs in Xinjiang have to be called Kazakhs?

This is a very impolite name. Kazaks in Xinjiang don't like to be called Hassa.

Kazaks in Xinjiang are not called Kazaks, but Kazaks or Kazaks.

Kazakh (Kazakh:? аза? / Qazaq /？ ) is a major ethnic group in Kazakhstan and a minority in China, with a population of160,000. In China, it is mainly distributed in Yili Kazak Autonomous Prefecture, Rem Kazak Autonomous County, Balikun Kazak Autonomous County and Aksai Kazak Autonomous County, with a population of 1.25 million (2000).