If being unable to sit down and spend hours pouring over text in a game when I am rarely actually home to do so is somehow dismissive, so be it. Some of us lead very busy lives, though I suspect mine will thankfully calm down a bit in the near future. Also, if you read anything I said as being presented as fact, it means you ignored words such as "suggested", "implied", "probably", "believed", etc.
Alright. Since you communicated a belief that racial tensions are the sole cause of people still bearing a grudge from the Civil War after nearly two hundred years have passed, I will give you a different example. Take a look at the Middle East, at Europe. Some of the countries over there have grudges that go back hundreds, sometimes even thousands of years. Some of these groups actively fight over it while others limit themselves to mere derision and other commentary. The point here is that people are really, really good at holding a grudge. Why, if people in real life can maintain a grudge over things that they themselves never personally experienced or that occurred long ago, is it beyond the realm of possibility for Garleans to have done the same?
Some of the worst world leaders we ever saw from throughout history got to their positions by preying on public perceptions. Even a certain German dictator took advantage of preexisting tensions to sway the masses over to his line of thinking. Why, then, is it beyond the realm of possibility for Emet-Selch do have done the same?