You can’t lose something you never had dude. WC3 happened, they left, changed their name. The blood elves do mention their history with the alliance, and they do so with disdain because in their eyes, the alliance simply was an ally who was largely unavailable.
How is it any fair for the alliance to get two themes to the horde’s one, when the HOrde was the original owner and a core race? This simply comes off as an entitled view.
“Well I believe i should have had it in the first place, so I should have it, AND this cool funky void theme too! Since I deserved it!”
Like I said, blood elves should get something new, but the view that the alliance deserves everything is an old mentality that needs to get dropped.