You see in Europe, we say high elf is a different elven ethnicity than kaldorei. , not a different race. Now troll woudl be a different rae, but you would likely say a different species.
Well, it is a little confusing if you're new, and if you're on the spectrum, but even those can learn the differences, but for most wow players, who've been around the block for a wile they should know by now the difference.
While blizzard hasn't outright stated that this is exactly what this is, it's kinda clear. The same thing happens in real life anyway, and irl is even more confusing as different groups get called different things both by different peoples and also in different times, , then mix and mingle too, forming new distinctions.
I personally don't think any clarification is necessary, the information is all there.. it gets freaky when you consider, terms like elf, high elf and night elf are often terms used in the common language, the speech of the elves is different, and I am suspecting they do not see themselves the way they are classified in character selection and most players do..which is from the human perspective.
I have gotten the impression that the elves really do not consider themselves as different as we do. I noticed that the high elves don't consider themselves as Highborne, but acknowledge their Highborne ancestry, but the Darnassians, like Tyrande have referred to them as Highborne ..to me that is even more realistic, because to an immortal like elf like Tyrande, being mere descendants is irrelevant. But to the descendants themselves who pride themselves in their independent identity not shackled or mired to the disgrace of the caste, it matters.
So were those pre-cata night elves in a sense using Highborne as a slur when they were regarding the blood elves? It's likely that it was received as a slur but not necessarily meant as one, just a matter of fact statement laced with contempt as it was made during the TBC pre-patch when the night elves were "warning" the alliance about the blood elves past and role in the War of the Ancients. .
But wait, the blood elves weren't around in the war of the ancients. Correct, but the Night elves addressing the alliance back then , regarded them as such - did they do so because they allied themselves with Illidan who had ties to the Legion and as such were repeating the same course of action the palace Highborne, of whom the Sunstriders were members were?
I have thought on these things, and that is waht I concluded.