In a 2019 review New York Times, writer Daniel Pollack-Pelzner accused “Mary Poppins” of the harmful practice of blackface, in which a non-black actor wears makeup to create a caricature of a black person. Mary Poppins apparently tries to circumvent this practice by having the protagonist and Burt (Dick Van Dyke) get covered in soot during a musical scene involving a chimney sweep. While one can try to make the argument that this scene does not share the same stereotypes as traditional blackface sequences, Pollack-Pelzner argues that the film cannot escape the book’s source material, which often used chimney sweeps for racist jokes.
Of course, at the time, some people on social media weren’t happy about it. @coldxman on Twitter believes that people were looking for racism as if it were like oil to be obtained and @jencon1978 believed that the context of the soot scene was not blackface practice. Whatever position you take on this particular issue, Pollack-Pelzner clearly felt it was worth discussing, and given how often people look at old movies through a modern lens, this conversation probably won’t stop anytime soon.