Give some context - Iran shares half of its borders with politically unstable countries, one of which has nuclear weapons. All of Germany's neighbours are extremely stable; they have better scope to look further afield for threats.
You misread me. Germans are safe from their immediate neighbours. Iranians are not. I'm not surprised that Iranians don't see the US as the most threatening thing around, especially given an unstable Pakistan with nuclear capabilities is right next door.
