Why do they like it?

People enjoy things that make the story feel real.

We may know from historical research that a barn stood on a certain site. That's not interesting. It's a boring fact.

What's interesting is the way it used to smell; the slippery dark wood; the day you walked out there and found a big old snake laying in the tub.

One hundred years ago, those things probably all happened. But we don't know for sure. We made them up. All we really know for sure is where the barn stood and we have a rough photo from 1888.

It's the little things (that almost HAVE to be made up, but are based upon what can be known) that would make that kind of tale interesting. I guess that's why well written historical novels outsell dry history tomes.

What johnrobinson said.

When we write historical fiction, it's like looking through a telescope the wrong way around. The main, undisputed facts are there but we are the ones who add the flowers and shadows, and make it a 3-D read.

This is from someone who also enjoys reading those dry history tomes.