Trump is a racist sympathizer.
He single-handedly used his wealth and fame to perpetuate the lie – wholly racist in nature – that President Obama was not born in the United States.
He has declared his intention to deport millions of law-abiding Muslims, ban immigration of Muslims, and has called Mexican immigrants drug dealers and rapists.
He openly accepted the support of avowed white supremacists during his campaign and has done virtually nothing to distance himself from these groups and their political aims since.
The neo-Nazi and white supremacist groups that marched in Charlottesville are similarly transparent in their purpose.
They believe in the supremacy of white European Christians over, well, everyone else.
In particular, they want to eliminate Jews and Blacks, and Latinos, Muslims, LGBTQ folks, feminists (perhaps women, generally), Catholics, and many others.
There is no mystery here.