Just because you call them two different species, doesn't make it true.
Night Elves and Blood Elves are the same species.
WROOOONNNNNGGGG!!!!
Honestly, Warcraft lore is enough of a mess without people spreading misinformation.
For the record: http://www.wow.com/2010/05/04/know-your-lore-elven-evolution/
What did I just say about misinformation? High Elves didn't even exist until thousands of years after the invasion.
You're wrong. In fact, even that article you linked says you're wrong.
The super short version:
At first there were Night Elves. You had the Highborne caste which practiced arcane magic, and they blew up the Night Elf capital. The members of the non-magic-using-caste were pissed, and exiled the highborne. The highborne set up on another continent, and the humans dubbed them High Elves. The High Elves then blew up their new capital city again (admittedly not their fault this time). Realizing that they were hopelessly addicted to magic, and would die without a source of magic, most of the remaining High Elves started enslaving demons and draining magic from them, and renamed themselves Blood Elves. The ones who didn't kept the name High Elf. Eventually the Blood Elves stopped sucking on demons, but kept the Blood Elf name.
Night Elf Magic-Using-Caste = Highborne
High Elf = Exiled Highborne
Blood Elf = High Elf that dined on demon magic at some point in their past
The exiles journeyed over the sea to Lordaeron, where they founded the kingdom of Quel'Thalas and began calling themselves high elves.
CALLING themselves High Elves. They didn't BECOME high elves for thousands of years.
Highborne are NIGHT elves.
Get your facts straight.
Highborne are High Elves AND Night Elves. Higheborne and High Elves are the exact same group of people. Pre-exile and post-exile is the only difference between them (And some skin paling up from too much magic usage).
THE EXACT SAME SPECIES. Same as you have whites, blacks, hispanics, orientals, and every other goddamn race on Earth all the way down to Eskimos, but they are still all the exact same species of humans. There are not multiple species of humans on the Earth anymore, no Neanderthals. Night Elves and Blood Elves, are the same species, but different culture, in different location in the world.
Night Elf = Highborne = High Elf = Blood Elf
Kaldorei = Quel'dorei = Quel'dorei = Sin'dorei
All the same species, just different cultures. Same species that keeps changing it's name.
Note the fact that Highborne are well known to be Night Elves (Hell just look up Queen Azshara), and despite the two races speaking different languages, it still EXACT SAME NAME as the High Elves in BOTH LANGUAGES.