Other Inspirations?
The truth is that Burroughs had lots around him to take inspiration from. During the time that he was writing, the fight against slavery was broadening out into a bigger movement against colonialism. And while attitudes towards race were fairly unapologetic, there was a feeling that in the jungles of Africa, the heroes were not the guys with the helmets and rifles.

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Another source of inspiration could be George Washington Williams, a Civil War veteran (who was played by Samuel L Jackson in ‘The Legend of Tarzan’). Williams was a human-rights advocate who, in 1889, fought to end the suffering of those in the Congo at the hands of Belgian colonists, who were producing rubber in the region. Williams brought to light the abuses on the Congolese people, and his trips to Africa were largely – something Burroughs would have known about.