Racism and Sexism in Novels Set in The Past

I've been finishing up a science fiction novel called Treasure of the Black Hole.  It is my attempt to take the 1940s and '50s film noir movie or hard-boiled detective novel about 4,000 years into the future.  It has spaceships and aliens and fantastic new technology, but it is written as an old detective novel such as Dashiell Hammett might write. In fact, I need to stick a fork in it and call it "done."

Part of the process of working on the novel (which was a NaNoWriMo project which shows how much more work it takes to go from first draft to finished novel) is I've had several beta reads and the majority of the readers have been women.  And I was surprised none of them complained about the sexism in the novel.

But why is there sexism in the novel?  Because there was sexism in the old detective novels. Now it's not horrible sexism, mostly confined to the way people talk to each other (e.g., a man saying to a female character: "You're a good man, sister"). And there's strong female characters so it's not completely sexist.  But I could see that someone could be offended.

And I'm having a similar issue with my work in progress.  It is set in 1881 in the American West (yes, it's a Western but with fantasy elements). But in 1881, racism and sexism were just the ocean everyone swam in. It was so prevalent no one even took notice (except, I'm sure, the victims).  So my character can't even think, "Gee, they sure treat those coolies poorly" because in that era, no one would think that except a few very enlightened persons.

For example, a major publishing house rejected my novel Agent of Artifice with a note saying that it was interesting but my hero was a "sleazebag."  The only reason I could think they would say that was that the novel is set in the 1950s and he is a womanizer.  So, yes, by modern standards, he may be a "sleazebag" but in the '50s he would probably be considered "suave."

In my novel Hammer of Thor, there are three uses of the N-word. Why? Because that's how people talked in the 1930s and '40s.

Sometimes when talking to people about novels they will be upset about the racism and sexism of books written decades or centuries ago.  But often, by the standards of the time they were written, they are radically not sexist or racist.  For instance, in E.E. Smith's Skylark of Space, the main female character is a very strong woman who speaks her mind. This in a novel written over 100 years ago. Yes, she has to be rescued and all that, but in a period when women were seen and not heard, she is in many ways treated like an equal.

Now, when we're writing novels today we don't have the baggage of writing them before the invention of the traffic signal.  But if our novels are set in the past, we have to make them accurate to the period, including sexism, racism, and other evils that we are today trying to get away from.  Presenting the realities of the past in a realistic fashion will do more to educate your readers on those realities than pretending they don't exist.