This has always been a nonsensical argument. Wicked may be hugely entertaining, but it absolutely is addressing contemporary issues, in ways that are eerily prescient.

I remember the story of Erich Wolfgang Korngold, who composed the legendary score for best-ever big screen Robin Hood (The Adventures of Robin Hood (1938), starring Errol Flynn). As a German who had fled his homeland due to the Nazis, he wasn't sure if escapist heroic romance was something he should give his attention. But when he read the script, and saw the themes of a people oppressed, and so forth, he wrote the score as a kind of anti-Nazi anthem. The rest is cinema history (and incidentally, that score was a huge influence on John Williams).

As a wider general point, the fantastic in art has often reflected contemporary concerns in metaphorical terms. Entertainment is not a dirty word, and the most important problems of our times are addressed far more compellingly when presented entertainingly. This is true across all genre fiction, from horror to westerns to science fiction, fantasy, and so forth.