No harm - no foul, especially when we’ve seen no reluctance on the part of lost causers to employ the words of socialists like Dickens, marxists like Lenin, and a garden assortment of yellow journalists - as long as their narrative fits their agenda.
Southerners have gone so far as to quote D.D. Eisenhower and his admiration of Lee.
So don't think twice about using W. E. B. Du Bois as a character witness.
Here's some other material from Wikipedia you can work into the narrative:
-After arriving at his new professorship in Atlanta, Du Bois wrote a series of articles generally supportive of Marxism. He was not a strong proponent of labor unions or the Communist Party, but he felt that Marx's scientific explanation of society and the economy were useful for explaining the situation of African Americans in the United States.[195] Marx's atheism also struck a chord with Du Bois, who routinely criticized black churches for dulling blacks’ sensitivity to racism.
-Also in the 1910s the American eugenics movement was in its infancy, and many leading eugenicists were openly racist, defining Blacks as “a lower race”. Du Bois opposed this view as an unscientific aberration, but still maintained the basic principle of eugenics: That different persons have different inborn characteristics that make them more or less suited for specific kinds of employment, and that by encouraging the most talented members of all races to procreate would better the “stocks” of humanity.
-Nine years after the 1917 Russian Revolution, Du Bois extended a trip to Europe to include a visit to the Soviet Union.[181] Du Bois was struck by the poverty and disorganization he encountered in the Soviet Union, yet was impressed by the intense labors of the officials and by the recognition given to workers.[181] Although Du Bois was not yet familiar with the communist theories of Karl Marx or Vladimir Lenin, he concluded that socialism may be a better path towards racial equality than capitalism.
-Du Bois took a trip around the world in 1936, which included visits to Nazi Germany, China and Japan.[210] While in Germany, Du Bois remarked that he was treated with warmth and respect.[211] After his return to the United States, he expressed his ambivalence about the Nazi regime.[212] He admired how the Nazis had improved the German economy, but he was horrified by their treatment of the Jewish people, which he described as “an attack on civilization, comparable only to such horrors as the Spanish Inquisition and the African slave trade.”[213]
-Du Bois opposed the U.S. intervention in World War II, particularly in the Pacific, because he believed that China and Japan were emerging from the clutches of white imperialists. He felt that the European Allies waging war against Japan was an opportunity for whites to reestablish their influence in Asia.
-In the words of biographer David Lewis, Du Bois did not endorse communism for its own sake, but did so because “the enemies of his enemies were his friends”.[262] The same ambiguity characterized Du Bois’s opinions of Joseph Stalin: in 1940 he wrote disdainfully of the “Tyrant Stalin”,[263] but when Stalin died in 1953, Du Bois wrote a eulogy characterizing Stalin as “simple, calm, and courageous”, and lauding him for being the “first [to] set Russia on the road to conquer race prejudice and make one nation out of its 140 groups without destroying their individuality”.[264]