This is Elder Scrolls. Ancestors and the Dunmer is good reading on this topic.

If I remember right, bodies act as a sort of gateway for spirits in the next world, through which they can interact, which is the precept behind the Ghostfence in Morrowind. That in itself isn't such a big deal however, as the spirits do not necessarily have any need to return to our world.

But in Necromancy, it's not just the corpses that are involved. You need a soul to bind to the remains - I don't think it's simple magical animation. There's a reason raised dead will occasionally plead for death - spirits often find our plane to be unsettling. On top of that, souls taken and bound to the body probably end up in the Soul Cairn after release, and if you've played Dawnguard, you'll know that's not pleasant.

Edited for minor clarification

Only those who are trapped in a Soul Gem are going to Soul Cairn.

no it really isnt. mannimarco might have attempted to take down the guild anyways but traven gave him both the resorces (necromancers who now hated the guild) and a good reason. without traven if mannimarco had attempted to bring down the mages' guild it would have been much better on the guild

edit: or maybe it reads differently to me

I thought it was any sentient soul who had been used for something. You could say having the soul interred in the rotting frame of a corpse was a similar process. It's not that clear, and UESP doesn't clarify that well on it.

Also I'm not sure what soul is used. It could be the soul that once inhabited the body, which would make some sense, as if Ancestors and the Dunmer is to be believed there is something to that.

Though perhaps the suicidal muttering of the corpse is just the physiology of the body itself, as it is proven in TES Online that bodies can exist without souls to a degree.

At any rate, Necromancy surely isn't known for the goodwill and cheer it evokes in people at its mention.

Oh and that thing about Mannimarco storing part of his soul in a gem reminds me of Harry Potter-esque Horcruxes. It's all a bit Voldemort.

It's a little confusing; I think some instances of raising bodies - skeletons, for example - might well be simple magical animation of the remains, without installing any sort of soul in them. Not sure about that.

Yes, it really is. Your argument sounds a lot like criticisms of the War on Drugs. To wit: If drugs were legal, there would be no crime associated with them. This philosophical outlook blissfully ignores all the violence, irresponsible behavior, and health consequences that these drugs cause regardless of legality.

Necromancy requires bodies. In order to practice the art on any scale, this requires stealing bodies from the grave; profiting from war; or murdering people yourself. In other words, actions that are morally criminal regardless of legal statute. Has it occurred to you that necromancy was banned not just out of prejudice, but to prevent dangerous criminal behavior? And that the people who are drawn to this art might be dangerous, morally unscrupulous deviants themselves?

in that case ban all magic. every school can be used to hurt, man, kill and slaughter people (or assist in the act), jsut because some people do bad things with it does not make it morally wrong. and i find nothign wrong with using a bandit's (or a rather long list of morally wrong people/things) corpse in necromancy, and i wont get into a moral debate about using other bodies

The point is that necromancy is a moral wrong regardless of the law; just saying "necromancy is not legal" would not make it right. Nor is there anything legitimate about using a bandit's body for any sort of necromancy - outside the possible exception of an immediate use in combat in circumstances where the alternative would be to die. But overall, other magic schools can be used for wrongful purposes, but all uses of necromancy would be wrong.

That said, my next character will include necromancy in his list of skills.

what is the difference between killing that bandit and raising it's corpse? if you are willing to kill it then you should have no problem with raising it, it is the lesser of two evils. and a lot of good can be done with necromancy (well not a lot but some), for instance, i could kill a few attacking bandits and use necromancy to make them protect a town, when other baddies attack the town i can use them aswell and it keeps going on and on till the town is really well defended, i have protected a town with no human loss other than what was absolutly needed (the only casualties would be something that has to die anyway)

Don't forget the part where many zombies "thank youuuuuu" when you kill them. That doesn't sound terribly much like they're enjoying themselves.

Though it CAN be argued that since you can soul trap someone then animate the body, that it's simply left over brain echoes. Either way, it's certainly not "good." Neutral at best, and likely evil. Either way, it's gross too.