Yeah, in 0.9 it lowered Magic Resistance as well, but it doesn't do that anymore. So it's absolutely useless for a bone necro, although summoners and poison necros can make good use of it (summoners can use it on Physical Immunes to help out their mages when Amplify didn't remove the Immunity).
Yes, it Affected Magic Resistance. It had the Effect of lowering it. If you catch my drift, Pherdnut.