"Mr. Wang’s access to United States consular officials during his incarceration may have been hampered by the nature of his entry into China. His lawyer, Chen Nansha, said he had entered mainland China from Hong Kong using locally issued travel documents, not his American passport. Americans who do not use their passports to enter China generally cannot obtain consular protection there, according to the website of the United States State Department."

This is EXACTLY WHY the CCP has started to force naturalized citizens to use the Home Return permit by denying them visas. It strips citizens of other nations of some of their rights based on what amounts to simple racism.