Quote Originally Posted by Kurald Galain View Post
Because evocation is about explosives and necromancy is evil.

No, those aren't the official definitions but (too) many people associate it with that. So a spell that creates energy but not explosive energy and not evil energy has to be conjuration.
+1

In earlier editions I believe that it WAS necromancy, but they decided that it didn't fit the dark/creepy vibe that necromancy has going on.