Minecraft wiki entry for Iron_Golem, associated text: A naturally-spawned iron golem becomes hostile toward a player who attacks a villager near an iron golem. Also, if a player has -15 popularity or less in a village, or has -100 or lower reputation with any nearby villager, naturally-spawned iron golems become hostile to that player until the player's popularity climbs above -15 and reputation with all nearby villagers goes above -100.