Which would've been perfect if Blizzard didn't then also try to have their cake and eat it by having NPC's commit drive-by exposition dumps.
Yes, the magic, itself, is necromantic. And Maldraxxus is its birth place of this necromantic magic. Necromantic magic comes from Maldraxxus. That is the canon.
And this works. It explains why the Scourge had such a distinct architecture and even 'culture' to it in Warcraft 3. It explains why whenever they show up, people with distinct robes and floating necropolis show up. It's rift through which Maldraxxus steeps. Without this, the scourge design doesn't make sense. So it's great that Blizzard resolved this, just like the resolved the distinct Icecrown architecture.
What does not make sense is saying 'necromancy is necromancy regardless of what magic powers it.' It's semantically correct but it doesn't hold up within this universe where there's such a thing as a realm from which necromantic magic flows.