I’ll say, “turning a neutral race into unwilling slaves is always going to be a terrible thing to do.”
And then you’ll counter, “desperate times call for desperate measures. Sylvanas’s entire people are in danger of dying out!”
And then I’ll say, “so what? Preserving the possibility of future ‘generations’ of forsaken have no impact on the wellbeing of the current generation. And besides, there is absolutely no reason to keep needlessly perpetuating the existence of undead people.”
And then you’ll say, “removing the possibility of future generations is akin to cultural genocide! Letting the forsaken die out means an entire civilization would be lost! That is equally as bad as forced slavery!”
And then I’ll say “if your entire culture is built around your identity of ‘being undead,’ that’s a you problem. There is no ethical reason that should become the problem of the val’kyr.”
And what will happen is what always happens; your perspective of Sylvanas and how you view the morality of her actions will always boil down to the question of whether or not you personally like the forsaken. Because, if you do, then you can forgive just about anything as long as it’s in the name of allowing them to persist.