"But they can't be so stupid to not understand that a nuclear explosion will wipe them out first," people keep saying.

It's weird because everybody has heard of those religious cults that collectively suicide by the hundreds. What was that guy's name, Jim Jones? Or the suicide bombers. They know they'll die. But they are fighting evil. They are going towards their reward in heaven! This is the same thing. The Russians aren't afraid of dying because they've been primed for their jihad for their entire lives.