Unless you are arguing that the "ETs" brought those aforementioned races in their spaceship with themselves and dropped them on Azeroth like you do when you buy a new fish for your aquarium, you're dead wrong.
All those races are original from Azeroth because they were born in Azeroth. They came to be in Azeroth. The means which they came to be (if it was through "natural means" or "outside influence") is completely irrelevant.
- - - Updated - - -
Yes, it makes you a Mexican. A Mexican with Chinese descent, but still Mexican.
Of course, that's talking about nationalities.