Depends. The goal of medicine school is to teach people to be doctors and help people. If you use your animated undead just to make your breakfast and do the heavy lifting for you, I am not convinced this can compare.
Or you're from a culture where the priest makes honored warriors into zombies, so that they can always protect the village, or the sacred areas. Such a fate being highly praised. Or that the undead serve as the protective force - even the weakest old man, in death, is just as strong as the next, so all bodies have use.
Or necromancers are literally medicine students; seeking to understand the body, and ways to beat death. See: Hollowfaust (Scarred Lands); city of Neutral/Good Necromancers.
Or necromancers are slayers of the dead/white necromancers.
And it also matters what raising undead does to the person of the origin body. In some variations, it could be that you are forcing the persons spirit into submission, or get ahold of its soul so it can't go to wherever soulds are supposed to go, instead forcing it into slavery to you.
I'm pretty sure that in 4e, zombies have no soul. They're just a body, and I think an animus (The primal spark). What you are describing is more like a juju zombie.
In general, in 2e-3e, I got the impression that PCs raising the dead was for the sole purpose of setting off traps.
Besides, animating dead in 3e was the sucker's way. All you have to do is play a neutral cleric, pick negative energy for your spontaneous healing, and get 'Rebuke' instead of 'Turn' undead. Now, use your turn attempts to make undead follow your orders. Tada!