Trump made a big deal about calling extremists, most notably radical Islamists, by directly naming them.  He condemned Obama and Hillary for not doing the same.
Trump has condemned BLM in the past.
http://www.foxnews.com/transcript/2016/07/19/donald-trump-have-to-demand-law-and-order.html
So we have evidence that he doesn't have problems condemning organizations based upon race.  However, Trump has yet to condemn white supremacists.  This event provides strong indication that he affirmatively avoids dong so.