In the middle of the Nineteenth Century everyone used the term nigger. Marx was a big fan of Abraham Lincoln and the civil war which freed the slaves. Liberating California from Mexico was progress from a land ruled by an Aristocracy of elite landowners who oppressed the peasants. America was a middle step on the road to what Marx believed would be the eventual rule of the peasants. It was the rich landowners of Mexico that he thought were lazy and contributed nothing.
The Nazis were socialists but there are a lot better ways to prove and argue that fact.
Obama is a black racist, a Marxist, and not fit to be President of the USA. We would object to a white racist as well. This is no way to run a country.