Immortality is their goal, so yes that is the point. They want to be undead and ever-lasting.
If we're on the point of Necromancy is only evil, then how do you view the Death Knight's stance? They are defacto users of Necromancy and transmit disease and death in all three specs. There is no real example of a truly 'Good' DK in WoW, every one of them is either evil or neutral aligned. They are still fully playable.
Are you trying to say that there can not be an evil-aligned class? Because if so, then explain the Death Knight in your own words. That they can not *choose* to be good aligned should not excuse them from being playable; by all means your argument is that Evil-aligned classes *can not* be playable.
A Playable Necromancer simply entails a neutral stance while still pursuing the dark arts; much like how Warlocks are perceived.
A soul is life. Life fuels Fel magic. The whole point of creating Soulshards is to capture life and consume it as Fel magic. They are destroying souls by consuming Soulshards. How have you missed this key feature?
Is that why Blizzard considered making a Necromancer class as far back as Wrath of the Lich King?
https://www.engadget.com/2009-01-29-...-released.html
"There were three front runners for the hero class to appear in LK:
Necromancer, a ranged caster with corpse explode and such. Some of this ended up getting incorporated into Death Knight
Rune master: "think rogue or monk type character"
And, of course, Death Knight."