You know. 4e has Warlocks who are tapping into Infernal power, or the power of Far-Realmsish entities. And there's no indication that these are evil acts. What makes Necromancy different?
The original meaning of necromancy is just summoning ghosts to communicate with them. There's surely nothing inherently evil in that. Actually, it has a lot of potential for 'goodness' since the information you get from the ghosts can often be used to lay them to rest.
And that makes me wonder.
Let's say that a necromancer actually summons/forces a ghost to fight someone.
How is that different than summoning any other monster to fight someone? A summoner basically plucks any other extra-planar being out of the multi-verse, points at his enemies and says "Get'm!" Your typical summoning spells for combat usage pretty much has the spellcaster compelling the summoned entity to fight for him - it's not a negotiation. And at least the 3e spells, you weren't plucking a specific entity out of the aether - it was just a random entity.
And in some cases, just tossing this out there, the necromancer likely isn't just grabbing a soul out of the underworld, putting a shock collar on it and sending it out to do badness - or making his own wraiths, etc. A Necromancer
could be doing the equivalent of going out into the wilderness, trapping a wild boar or tiger, and training it to fight beside him - the Necromancer is tossing a leash on a wraith and binding it to his will. Is it evil to control an evil entity?
Granted, I'm a bit biased here. I'm willing to go so far as to say that some forms of
undeath aren't even evil.