If lower than Oblivion, I am sure a certain Hlalauu alchemist, if still living, might make an appearance.
Necromancy to me means preparing a corpse, and reanimating only a body, and controlling it via magical incantations.
The bosmer gift of turning the undead therefore goes against the teachings of Arkay. Then again, they consume their enimies. Does that excuse necromancy?
Conjuration is the summoning of whatever magical essence of being: spirit or monster, to do your bidding. Whether or not that being decides to take a corporeal form is up to them.
First part seems to be in-line exactly with the
only book on the actual art of necromancy. Prep, reanimate (no mention of souls being used, for all of you out there), and control (or else they stand there like a dummy, from what it seems).
But...with point number two, it's more like the bosmer don't like necromancy, because playing with your food is wrong. Doesn't go against Arkay's Blessing, as one isn't reanimating a dead body, which Arkay's blessing prevents. The bosmer just eat the person they killed, and will allow family members to join in if it's too much food. This is also why it's hard to be a necromancy in Valenwood, because the raw material is food for everyone else. Also, Arkay's Blessing only prevents someone from using a dead body. However, the rite needs to be enacted, or else the person's corpse can be used willy nilly by any mage. This is why those who practice the craft of necromancy find battlefields a good place to get raw materials, as many bodies would likely be buried or left to sit without a priest of Arkay to enact the blessing on the dead body.
And with summoning, with daedra summons, the conjuror bind the daedroth to them and, pretty much, controls them through willpower and skill. The process does require the user to concentrate enough, or else the daedroth will ignore the user and start doing whatever it wants, as seen with how a few apprentice conjurors of the Mages Guild caused some scamps they summoned to get out of their control. With ghost and wraith summoning, I see that as ripping a soul out of the Dreamsleeve and forcing it on Mundus. With the skeletons and zombies in-game, I see that as EZ-Necromancy. Too much effort to collect body parts.
But seriously, people, On the Preparation of the Corpse is the only book that actually describes the craft of necromany. Flip through it, as it also gives some insight on how other cultures view necromancy (legal everywhere, save for MW the Mages Guild).