"'just a metaphor and means something completely opposite'."
First a lesson in figures of speech: a metaphor is a word used in place of another to suggest a likeness between them. Otherwise, when we take the bread in communion we would think we were actually eating the church, the body of Christ.
Next, if you look closely at 1 Cotinthians 12, you will see the Apostle using many metaphors for the members of the church; eyes, hands, arms, feet etc.
And if you really look closely you will find there were many denominations in the early church, in fact each city was its own denomination. In Jerusalem, the center, there was the Hellenistic church and the Jewish church. In Corinth there was the church that followed Apollos, the church that followed Peter and the church that followed Paul.
nothing says metaphor like:
1Cr 14:37 If any man think himself to be a prophet, or spiritual, let him acknowledge that the things that I write unto you are the commandments of the Lord.
UNless the sheep and goats MUST be separated and that is one way of doing it..
i.e. hiding the truth by metaphor.. The "eat and drink(my body, my blood)" metaphor(s) is only one of them..