In the manifesto, Roof discusses Trayvon Martin and ignorantly asks: 

"How could the news be blowing up the Trayvon Martin case while hundreds of these black on White murders got ignored?"

What appears to be Roof's reasoning behind his take on different races as well as white supremacy is also discussed in his manifesto. 

He claims that because of his "research" he had become "racially aware". 

Dylann Roof goes into discussing "Jews", "Hispanics", and "East Asians" aside from "Blacks". The terrorist talks about how white people don't feel as if they have a "unique culture because their culture is world culture", the problem with Jewish people is that they "look white", there are "good Hispanics and bad Hispanics" and he believes that East Asians could be "great allies to the white race" as "they are by nature very racist". 

Read the full manifesto, here.