Hate is a far more potent emotion than love, Stilly: a red rage takes rather longer to wear off than a pink glow. That's why political attack ads work. If you can get the masses to hate someone else (eg foreigners) enough, you've got a zombie army at your command.

.... Just make sure that, when you're leading your zombie army, you don't trip over. Oh, and aim at the institutions of learning first, as critical thinking is Kryptonite to a berserker.*

* Apologies for crashing gears in mid-metaphor without using the clutch.