But let`s just look at it again. Nothing existed on Azeroth from day one. Everything that on Azeroth came into being long after that point. Some were created. Others evolved.
This is an interesting concept... The Earthen and Earth Giants, for instance, were created from the rock of Azeroth and given life by the Titans. While they were created by non-natives, does that mean they are non-native themself, despite their whole existance starting with Azeroth?
In a similar way, if you genetically engineer a native species into something else, is it now non-native?
External agency is a bothersome thing.