The problem with the "reflect the era" argument, though, is that even then, there were people who recognized racism as wrong and refused to perpetuate racist stereotypes and tropes in their fiction -- e.g. Jack Benny, who cast Eddie Anderson as Rochester rather than having a white actor do a "black" voice, and who forbade his radio and TV writers from resorting to stereotype humor when writing Rochester. Or director Jacques Tourneur, one of the only filmmakers of his era to portray black characters in non-stereotyped ways. Even then, there were people who knew better. So the people who uncritically embraced the tropes weren't entirely innocent.