Joseph, the alt-right is a rebranding of white supremacism. The term was invented by Richard Spencer, who identifies as a white nationalist (and wants a Jew-free homeland for whites only in America.) At first, the term was used in different ways (when Bannon referred to Breitbart as a platform for the alt-right he may not have meant white supremacists). There are some non-white supremacists among the alt-right, such as the neo-fascist group the Proud Boys. But in general, the term is now used to refer to right-wing extremist groups, either explicitly racist or anti-democratic pro-fascist.
Regardless, look at non-wikipedia sources and you’ll see the same thing — the individuals and groups who organized the Unite the Right rally were all racists — whether they are new-style rebranded “white nationalists” or old-style neo-Nazis or KKK. The point of the rally was to unite the different extremist groups.