Sylvanas fancied she had reasons to oppose the night elf people, too, and they were far less personal than Vereesa’s. And none of them matter to the people she victimized.
Vereesa leads (led?) a faction dedicated to thwarting Silvermoon’s interests and instigated a population purge of Silvermoon’s people. Sylvanas is cognizant of the antipathy her antagonism has generated among Teldrassil’s people and her little sister should feel much the same about a reunion with Silvermoon’s. It’s ridiculous that her prospective return doesn’t even allude to the elephant purged from the room.
If I’m Vereesa, an avowed anti-blood elf cursed with visions of a blood elf apocalypse, I’m really worried about how the blood elves are going to take this news from me, of all people. “Azeroth must be crazy,” I’d say, “and they’d be crazy to believe me.”