If the inhabitants of a city follow an idolatrous prophet and refuse to repent, God says the entire city and everything in it is to be destroyed. (Deuteronomy 13:12-17)

That's how seriously God views idolatry and taking his name in vain. Freedom of religion is great within the boundaries that God has set, but the worship of any deity except YHWH shouldn't be tolerated. Despite modern political dogma, idolatry is not a victimless crime. It poisons the whole people and damages their relationship with the Creator.