This jerk is just plain stupid.
It's been established that talented new graduates are level 15, and the very elites who can push to 16 are exceptional.
And necromancer guy comes in on first day at level 17. With a title of "national champion" to boot.
Either he's just lashing out without knowing anything, which is already dumb enough, or he's stupid enough to lash out knowing the circumstances, which is lethal-level dumb in that world.