It's sort of funny, i've never really thought to compare the recent advances in medical research and technology to necromancy, even though there are similarities worth noting. I suppose this is primarily because the practice of necromancy was always one steeped in religion and mysticism, and not heavily linked to scientific advances in the same way that a tradition such as alchemy was. However, there is also a distinction of intent. In ancient times, as far as I know, most texts about or referencing the practice of necromancy mentioned it with the intention of communicating with the dead, either in spirit or through a physical medium. That being said, the primary focus was very much on the aspect of communication. The physical body was used as a temporary vessel to be spoken through, not often with the intent of long-term revival. Though I am certain this varies between cultures and time periods. I will say I think your choice of classification in a fantasy setting is interesting, and I would make a similar separation between a practical school and a more conceptual one. This is actually a relatively common method of categorization because philosophical pondering is seen by most as impractical by nature, so usually there is some level of divide between applicable practice and theoretical questioning. Coexistence of both is necessary, but they're still kept to either side of the drawn line.

Theoretically, in regards to using the body to communicate with the "spirit", we have begun to be able to bring back dead neural tissue, something that could allow us to "communicate" or at least "see" the memories and activities of the dead given a bit more time and tech. Imagine, say, being able to resuscitate the mind of a dead man and find out who killed them by seeing their last moments. And yeah, as to the distinct breeds of Necromancy in a fantasy setting, I tend to muse on things like that a lot. I've come up with quite a few interesting thoughts on it. Though, fascinatingly, both schools of Necromancy are a bit more contradictory to each other. Since one has no concern for the spirit, while the other sees it as the entire purpose of things.

Bringing back neural tissue is a step in the right direction, but there are certain issues with the current process. The main problem being that necrotic neural tissue that has already begun to break down, even if returned to a functional state, won't necessarily hold the same information as it did prior to its cessation of function. It would essentially be as though the slate were "wiped clean" of any prior experiences linked to it. Ordinarily, the only time that this isn't the case, is when resuscitation was successfully performed prior to the death and decay of the individual neural cells. Though, this could potentially change as new discoveries are made in the subject of neuroscience. And I think that contradiction/distinction between these two schools of necromancy is primarily where we find where most people distinguish between the "moral" practice and the "immoral" practice. To most people who believe in a spirit, they equate a spirit to a sentient, living creature. And as such, believe that the spirit should be attributed the rights that we typically attribute to the average adult human being. That is, the freedom of independence and freedom of choice. If a necromancer warps a spirit to do their bidding without seeking consent, from this perspective, it would essentially be comparable to slavery/forced servitude.

True, true, but that is something that is still being worked on. Assuming the death wasn't too long ago, recovery of at least a decent amount of data is still possible, assuming preventative measures are taken. We might not be able to pull full information, but we can still speak to the dead that way. Also, in a way, we've reached a semi-form of the divination-based form through contemporary corpse analysis. We can find why an ancient individual died, see what had ailed them in life, see what they ate, what they wore, practically every aspect of them. In a way, isn't that a form of talking to the dead? And true, that's the big part of it. Also, the pseudo-scientific aspect of the body. Practical necromancy pays little attention to the completeness of the ones they call on, besides functionality. They'll happily piece together minion out of a myriad of corpses, or alter the body to fit their needs, whereas a "true" necromancer will attempt to preserve the body of the one they want to raise, in it's full integrity. Also, with regards to the spirit, most "practical" necromancers don't actually touch the spirit, instead merely creating a simulacrum of rudimentary intelligence. Be a terrible bother if your assets suddenly started resisting, after all. So in that regard, I feel that it falls more under keeping a person's mind isolated and making them watch as their body is manipulated.