Gonna try and point out something many are missing .
Faerun. Isn't. Earth.
Faerun has what we refer to as technologically medieval. No tanks, lasers, computers, cars, and the like.
Other than that, it is NOT a homogenously medieval equivilent to Earth in terms of culture, government, religion and so on.
Faerun has City -States, Autocracies, Monarchies, Oligarchies, Republics, Empires and even a nascent Democracy or two, at one point or another. Medieval Earth did not have quite the same breath of governments.
Earth in medieval times had wars and conflicts due to religion, but it was generally on BEHALF of Yeewah, Allah, Christ our Lord and Savior, and a wide variety of eastern gods- - however, last I checked, Yeewah wasn't popping in for dinner and chat, Allah wasn't sitting in on a King's counsel personally to plan his next conquest. In Faerun, the Gods are a reality, making themselves known on a personal level and interfering with each others plans in a way that did NOT occur on Earth.
Even on Earth during medieval times, race distinctions did not automatically lead to fear, suspicion and hatred - there were still many cosmopolitan cities that were home to various races, and other lands that were far too busy hating and fearing the clan down the road - forget distinctive races. Call it what you want, but Saxons and Celts were NOT genetically distinctive races - nor were vikings - simply different cultures. According to Western lore, Egypt welcomed the Jews - then later enslaved them. This had nothing to do with being a medieval society - it was politics.
And even in medieval times, trade often trumped all other consideration - if you needed spices, oftentimes you did not give a damn if the trader that called on your town once a year was of a different race or culture - you just bought the damn spices and were happy to get them.
Determining how the societies in Faerun - a made up world - based upon what real world culture was is ridiculous. You might as well determine Star Wars in accordance with Jude-Christian belief structures or Star Trek with as analogous with modern Socialism, or whatever theoretical mind candy one wants to chow down on.
