Dude, the article is entitled 'What Black AMERICA Needs From Biden's First 100 Days'. I think it's pretty clear, therefore, that “worst politician in history” is talking explicitly about American political history. Had the article been titled, 'What The World Needs From Biden's First 100 Days', I'd be fully on board with your comment.

Yes, the writing could have been clearer, but the context is clear enough.