I'm fine with there being differences. In fact, I tend to prefer worlds that are very very different from history. Which is why I mentioned that the closer to history it is, the more things like lacking a Jewish analogue bug me. For example, in one fantasy series, there's a fully fledged Rome analogue, a Byzantine analogue, a medieval Catholic Church analogue, mystical heresies, and a Middle East. They're even probably on the cusp of a Reformation. Still no Jews. The closer to real history you get, the more jarring the absence of oppressed people, especially ones who played a big part in that history. Then of course you get to the whole sets of history we happily ignore.

There are sometimes I like a world with no constancy, for example, Alice in Wonderland and The Phantom Tollbooth (yeah, I like shiny shiny kitchen sink novels) but I just get annoyed when authors happily copy bits and pieces from other novels and from history and cobble them together with no consideration for whether or not the whole works.