I agree with those who say we shouldn't make the Eucharist political, but when priests and bishops preach about who can and can't go up for holy communion it's not about politics. It's about religion, as in our relationship with God. If we want relationships to last, honesty is important and lying in a relationship matters quite a bit. That's especially true in our relationship with God. In relationships between man and woman, we can lie with our bodies by having sex out of wedlock. In our relationship with God, we can lie with our bodies by walking up to communion when we are not in communion with the Church.
The altar is the bed chamber in the marriage between heaven and earth. Communion is the greatest act of intimacy between God and his Church, just as sex is for husband and wife. The ciborium, or baldachin, in St. Peter’s Basilica in Rome and other traditional churches represent this mystical reality. St. Peter's baldachin was built during the pontificate of Pope Urban VII between 1623 and 1634. Pope Urban VII was of the Barberini family, a prominent family in Rome at the time. The baldachin in St. Peter's Basilica has engraved on it the Barberini coat of arms, which depicts three bees. Read the description of the baldachin's coat of arms in this Wikipedia article:
This series of eight, nearly identical coats of arms forms a narrative that has attracted over the centuries the interest of writers and art historians. The coat of arms itself represents the three bees of the Barberini family.... The allegory behind the coats of arms is universally interpreted as representing the various stages of childbirth. As (Gustave Joseph) Witkowski writes:
The scene begins on the face of the left-hand front plinth; the woman's face begins to contract; on the second and following plinths the features pass through a series of increasingly violent convulsions. Simultaneously, the hair becomes increasingly disheveled; the eyes, which at first express a bearable degree of suffering, take on a haggard look; the mouth, closed at first, opens, then screams with piercing realism. ... Finally, comes the delivery: the belly subsides and the mother's head disappears, to give way to a cherubic baby's head with curly hair, smiling beneath the unchanging pontifical insignia.
Christ's sacrifice on the cross gave birth to the Church. The altar is where we commemorate that sacrifice. Through the Blessed Sacrament, the Church has been giving new life to disciples of Christ for ages. When Christ gives us his body in holy communion, he is providing seed for the Church. Since bees spread pollen seed for numerous kinds of plants, the bees on the Barberini coats of arms--at least in this context--could also easily represent the spreading of life, since that is what Christ is doing when he gives us his body, the bread of life. The pain in childbearing depicted on the baldachin could symbolize the sacrifice of the martyrs, who Tertullian called "seed for the Church". The symbolism here is that the Church's suffering bears new members, just as a mother's suffering in giving birth bears a new child. The allegorical art on this baldachin depicts this mystery, but over the centuries we lost the plot.
It makes sense that the meaning of communion has been lost in our modern age though. After all, the meaning of sex has been lost as well. People have sex out of wedlock as casually as they walk up to communion while not in communion with the Church. If I have sex outside of marriage, I am lying with my body because I am saying the other person and I are one flesh when we in fact are not one flesh in heaven’s eyes. With my body, I am saying the woman and I are one, but since I have not devoted my life to her my heart and soul are saying something different. If I receive holy communion while not being in communion with the Church, I am lying with my body because I am saying, by receiving, that I am in communion with the Church, when I in fact am not in heaven’s eyes. If I have mortal sin on my soul I am not in communion with the church.
What is worse, when we receive communion in mortal sin we are forcing Jesus into our bodies against his will. We are forcing him to commune with us in the most intimate way we can commune with him here on earth, when his heart and spirit and ours are not one. It's not consensual.
I'm not saying communion equates to God making love to humanity. Rather, the marital act is an allegory for the sacrament of communion and the proliferation of eternal life. We can never fully understand the mystery of communion this side of heaven, but the marital act gives us a glimpse of that mystery that we can understand in our mortal, fallen bodies. When we sin we've been unfaithful to God, and the sin is allegorically parallel to being unfaithful to our spouse. The bond formed between us and God through the other sacraments needs to be restored through confession.
If we continue to hold to beliefs contrary to the Faith as we go up for communion, we are lying just the same as if we committed a mortal sin and did not confess, because we are saying we are in communion with the Church, while our beliefs and its teachings are not the same. It's not about worthiness. It's about communion. If I am not in communion with the Church and I receive communion, I am saying with my body something I don't believe with my heart and soul.
We should only have one spouse because our hearts only have room for one if we are loving him or her right. We should only have one Lord, Jesus Christ, because our hearts only have room for one if we are loving him right. The parallels between marriage and our relationship to Christ can go on forever, and we probably won't know the fullness of it all until we reach heaven.