Minecraft wiki entry for Things_not_to_do, associated text: If the player's popularity is -15 or lower, any naturally spawned iron golems attack the player without being provoked. Also, the village popularity does not reset when the player gets killed and the only way the player can get their popularity back up is to trade with villagers. So the player should only attack villagers or iron golems in special circumstances. If a villager or iron golem must be killed for some reason, the player should contrive to use natural damage such as fire, lava, or dispensed TNT. Iron golems do drop iron ingots upon death. The player can also build an iron golem farm specifically to collect iron ingots. Remember, villagers are the player's friends, not their foes!