Blood Elves and High Elves are the same race. Period. Two different political factions of the same race.
Void Elves, on the other hand, are no longer the same race.
We have three groups of Thalassian Elves, one GMO Thalassian offshoot race who are formerly members of the Blood faction of the Thalassian race and two non-GMO factions of that race.
Genetically Blood Elves are High Elves.
Politically and philosophically there are differences. One group turned their backs on 90% of their kind, refused to honor their fallen, and refused to aid in the rebuilding of a Scourge-shattered nation and instead chose the safety and comfort of Dalaran, Stormwind, Theramore (until BOOM) and a hunting lodge. One group struggled to survive and rebuild that nation while honoring their fallen King and their fallen brethren.
Bloods and Crips; mortal enemies, both human, both the same race.
Hmmm…maybe if we renamed High Elves Crips we could bring west coast elven gang warfare into warcraft. Bloods and Crips, Elves at War