No Coffee???

Why has the church defined "hot drinks" in the "Word of Wisdom" as tea and coffee? Is it because they are hot? No, there are other hot drinks such as Postum, hot chocolate and herbal teas that are alright. It is the caffeine in those restricted drinks that we are warned against. So, can we consume caffeine in other forms and think we are really complying with the "Word of Wisdom?" Must we be commanded in all things?