It's not If it was the name of the race you would have Queldorei named Npcs in the Horde but you don't have any of them. The Alliance does
Night elves, blood elves, High elves, void elves, shaldorei are all part of the same race. A race divided in different groups of elves.
High elf is the name of the group.
Blood elves corrupted themselves then welcomed redemption. High elves as a group stayed with the Alliance and or went neutral but never tasted any form of corruption. That's why a blue-eyed blood elf will remain a blood elf because a sin'dorei is not a queldorei.