1 Moral statements have truth values
2 There are good and bad arguments for the moral positions people take
3 Nonmoral fact are relevant to the assessment of the truth value of moral statements
4 There are moral facts.
5 When two moral statements conflicts as recommendations to action, only one statement can be true.
6 There is a single true morality. page1 "Moral Relativity" David B.Wong
David B. Wong rejects 5 and 6 (page 7) (---think of how to reconcile Rawls and Nozick, or the controversy over abortion---)and hold moral relativism and coupled with the premise that it is wrong to impose one's view on another person unless one can justify them to him , he derives the persuasive theory of tolerance.
Probably his ethnicity is not unrelated to this conclusion. Ethinic Chinese have been imposed western values and the mother country had constantly intervened by western countries; it is not difficult to imagine that a professor of Chinese background, one way or another, has arrived such a view.