Pakistani Prime Minister Imran Khan’s foreign-policy agenda carries a contradiction at its heart. Mr. Khan seeks to project himself as a global defender of Islam, but he won’t utter a peep about one of the most egregious persecutions of Muslims: China’s repression of Xinjiang’s Uighurs and its project to Sinicize Islam.

In New York last week, Mr. Khan laid out his vision in a rambling 50-minute address to the United Nations General Assembly. He defended the right of Muslim women in the West to don the hijab. “A woman can take...