>>85628495AD&D's arcane age box sets had it.
Myth Drannor, during the arcane age, was obscenely powerful and ELF ONLY, FUCK EVERYONE ELSE.
Over the course of its history it dealt with various issues and problems, ranging from monsters, to demons, to mad netherese mages, to refugee issues related to world events happening at the time, where they mostly turned people away.
Over time they started to accept people into society as long as they could prove themselves useful, then eventually they started letting everyone in, however I don't remember if it was that box or Grand History that established that if you weren't an elf, you had to be a mage or you were a second class citizen.
So the Harpers celebrate this time of Myth Drannor's history where they were a bustling magical empire where all races are welcome, because much of the truth of Myth Drannor from that time period is lost forever, and what isn't lost forever says they had loads of different people in it.
Also the fact that the fall of Myth Drannor was started by a human wizard doing gene-splicing experiments with dragon eggs really goes further to say that if it weren't for the elves allowing the netherese mages to live, Myth Drannor would have survived.