The Altar, the Prophet, and the Lion

The Ish Haelokim's refusal to eat on his mission against Yerovam and the new form of worship in Beit El stems from God's command which proves the chastity of the prophet. He is not a paid prophet, but loyal to God, Nonetheless, when he disobeys God's word he dies at the hand of the lion. This is symbolic of the confusion surrounding Yerovam. On the one hand he is ordained by God in Ahiya's prophecy. On the other hand he is disobeying God in the new system of worship that he set up. He is given an opportunity to repent but rejects it. 

Are the Golden Calves of Yerovam considered Idol Worship or an alternative but prohibited worship of God?