he won’t because

1. he loves playing the game of dancing around the word and issue of racism because he thinks it makes him look smart, but it just makes us all see how racist he really is
2. he doesn’t need to because he is able to employ (and even invent) a litany of racist dog-whistles instead to get his points across.
3. the man is such a blistering boil of pus and hate that the N-word is… forgive me for saying… beneath him. His racist rhetoric operates at a much higher level than simple slurs.