Historical fiction always serves the didactic purposes of the present.
Parallel periods comment on today in the sneaky revealing light of yesterday:
Mexican-American War = Iraq-American War
or Classical parallels used earlier:
Imperial Rome = British Empire; Persian Empire = France
Periclean Athens = Britain or France; Sparta = Prussia
Periclean Athens = France; Persian Empire = British Empire (French writers, of course).
Writers explain or glorify the present, or amend past indignities, via histfi. Sir Walter Scott single-handedly rehabilitated and glamorized the Scottish, despised by the earlier Georgian English as uncouth demi-barbarians.
Think of racist images recently over-painted by more realistic or positive characters, whether protagonists or secondaries. This can go too far, into anachronism, as when the Noble Savage is revised into a culture missing notable unpleasant aspects it actually had in order to make it fit what today considers ideal or acceptable.
Distorting the main characters or their culture with the bias and behaviors of today can make histfi extremely dated in a few years. You can pretty instantly spot bad histfi or bad historical fantasy when you pick it up and go, “This sounds like people out of the 1950s!” or whatever date turns out to be when it was written, or the author’s attitudes formed. People can write their historical worlds as a way to revive that of their youth: that is, they re-create the 1970s in the guise of the 1670s, or the 1980s as the 1850s.
We call this syndrome “your friends in funny clothes” (YFIFC): the Good Guys all know in their hearts that they should be thinking like us, and they do, while only Bad Guys have authentic politically-incorrect attitudes of the time. This often sets up straw-man obstacles for the protagonist to oppose righteously, like slavery, racism, religious bigotry, and other dead horses flogged for 100,000 words — fake because little things like economic realities or actual laws never stop them from freeing all their serfs without the okay of their feudal liege, or giving their wives property when married women could own not even the clothes on their backs. They’re preaching to the choir, anyway, because we already (well, most of us) decided decades ago that these were bad things.
As a challenge, as an author of historical fiction, try to show us why otherwise sympathetic people could or had to accept these things because of the world around them.
You may identify too closely with your main characters, love them too well, to have them behave and believe like all those wrong-headed jerks back then. Maybe you should try making them time-travellers instead, or setting this in another world rather than another time.
You won’t get it wrong if you really get into your period. Those traipsing too lightly through the past are at risk. They believe “People of other times were pretty much like us.” This simplicity saves them the travail of having to think like a different culture or learning to converse in Standard or past English, since these writers inevitably “translate” all dialogue into TV English, full of modern slang and jargon — and modern concepts. ‘Twas the one who didst so whilst putting forsoothly stuff into the narrative who completely baffled me.