Read your argument ... tell me how you make any sense because any Void elf was a High Elf at one point as well and most are implied to have been Blood Elves.There are clearer differences between the two you mention and Blood Elves vs. High Elves.
Example A) High Elves can be born the same skin color as Blood Elves. There is no reason they couldn't.
Example B) Blood Elves can have blue eyes. Why couldn't they? The Fel color has clearly gone away, it's entirely possible a Blood Elf that isn't super duper "For the Light" simply didn't get golden eyes.
There is no visual difference to the two. Meanwhile, Void Elves not only have literally black skin (Didn't exist before with Blood Elves), but pecs bigger than any Orc in game currently. Does it make sense? No, does that make it not a thing? No. They are visually and culturally different - Blood Elves worship the Light, Void Elves are beings of Void - Literal total opposites.
Nightborne don't share ANY traits of the Night Elves except their general model. Purpler skin color, stark white eyes, arcane tattoos, no reverence of nature... Literally completely different beings.
Meanwhile, not only do High Elves and Blood Elves share a culture, a history, and a general appearance - They're literally the same people. Any living Blood Elf of a reasonable age WAS A HIGH ELF AT ONE POINT. You can't separate the two as long as this continues to be true.