My reading of the scripture in question differs from that of the Pope. But I don't believe the Pope's proclamation on this subject is an infallible decree so I suspect there is room for disagreement even among Catholics.
IMO it is not unconfessed sin in your life that will bring destruction at the communion table, but an unworthy or cavalier attitude towards the sacrament. Indeed, I think that if you approach the sacrament with the attitude that you, yourself are "worthy", then you are likely to take a cavalier attitude to the table.
No human being has ever been "worthy" to partake of the blood of Christ. We are honored that God has provided us the opportunity in our unworthy state. That is the essence of God's grace.
Thank you for inviting me to stick around. But I will probably keep my posts to a minimum.
I'm not clear on what you believe about the Eucharist? It's either a symbol or the body and blood of Christ, it can't be both. If it's a symbol, why all the fuss about being worthy or unworthy?
Let us step back to the issue of mortal sin first. It is not the criminality of the sinful act that makes it mortal, but defiance of God. Mortal here refers to the deadening of the soul. The arch-sin that is mortal is denial of sin, as in Eve's denial of the sin of eating the fruit based on the reasoning that the fruit looked edible. So, a vile murderer who confesses and repents is free from mortal sin, and can receive the Eucharist, and someone, for example, who is aware of the Catholic teaching on contraception but contracepts without confession, may not, even though the latter transgression is small from the secular standpoint.
As you see, a mortal sin is indeed a cavalier attitude toward God. When someone thus burdened approaches the Communion rail, this becomes a cavalier attitude about the Eucharist. So, you are correct.
You imply another quandary: if a communicant is aware of absence of mortal sin (because, for example, he just completed confession and penance), is that an assumption of worthyness, in itself deeply sinful? The answer is that communion is only valid in the context of Mass, and the proclamation: "I am not worthy to receive" is made, as a necessary mart of the order of Mass.