Technically, yes, she is a High Elf. Void Elf is a mark her people took upon themselves after dabbling and connecting with the Void, which they did in attempt to aid the Thalassian lands, and were sent away due to it.
And? It is story? Though, roleplayers see it as a joke the "Not a DK" excuse people made to have High Elves back in the days. It is a story they play with the character they made. Does it hurt you? Not really. Does it offend you? Not really. Do you have to rage? Not really.
I take it you don't talk with many people? I've seen members of the Alliance ask for undead characters to be able to interact with the Alliance in the form of being part of, or removal of factions. Nothing new. Alliance players even wished for some "Friendly" method of Night Elves and Tauren to work together as they were known to do, and not have to be forced to be druids to do it. I have seen Horde members wishing Worgen was part of Horde as well, even Dark Iron Dwarves.
But you do you, raging on the floor, don't pop a vessel just because players have options that don't even harm roleplay.