will extradite them to mainland for prosecution because they have been used to a western style of legal system.  They want to remain in what they say, a fair and free legal system of which Mainland China does not have. If you were in their position, you might also be resentful to that proposal. They don't want to be trialed behind closed doors.  The sad part is, US will find every opportunity to intervene in China's domestic affairs.  This is where US has the advantage.  Washington will be satisfied if Hong Kong, Taiwan, Xinjiang are hostile toward China.