A Harvard visiting professor and modern slavery activist exposed the “appalling” cobalt mining industry in the Congo on a recent episode of “The Joe Rogan Experience” that went viral. The video has already racked up over one million views and counting. Siddharth Kara, author of “Cobalt Red: How The Blood of The Congo Powers Our Lives,” told podcast host Joe Rogan that there’s no such thing as “clean cobalt.” “That’s all marketing,” Kara said. Kara told Rogan that the level of “suffering” of the Congolese people working in cobalt mines was astounding. When asked by Rogan if there was any…