A related point is that no time is a monolith. I've been reading mysteries from the first quarter of the 20th century lately for instance, and I notice that the Raffles stories are a lot more anti-Semitic than the Dr. Thorndyke mysteries (the latter have lots of Jews, both sympathetic and not) and that the Father Brown mysteries are far more racist than either. (And even more racist than I'd noticed on previous readings; apparently I find it harder to give older books a pass these days.