Let’s take this a little more simply.
We who are communicants know, by observation of ourselves, that consumption or skin/tongue contact with Our Lord’s Body and Blood does not kill us or make us vanish. It is the experience of the Church that dropping a Host on a plant or having an animal touch it does not kill either of these kinds of living creatures. It also does not melt the ciborium or the chalice, or the altar linens or floor if (God forbid) the Host or the Precious Blood is dropped or spilled.
So if the Lord doesn’t smite large living creatures or large non-living creatures for touching Him (though of course He could if He wanted to), one would assume that He also would not smite those tiny but well-loved microorganisms which He created. They are not evil, though in this fallen world they can harm us. They are doing nothing wrong, that they should be smote out of existence.
If they are alive and sitting on the accidents, they can get on us and in us, and they can make us sick. That’s natural law, which God made and loves also.
It is our responsibility to treat receiving Our Lord with respect, and not to spread sickness on a chalice that other people will have to touch with their lips. It is not His responsibility to spare us from the consequences of our fellow Catholics’ folly or disrespect. Generally we don’t get sick that way, or we don’t worry about it; but exercising prudence in such a matter is respectful.
Otherwise, it would be totally okay to use Father’s wiping cloth for the chalice to wipe our own noses, on the grounds that God would keep sacred objects from passing on sickness. But the point is that we shouldn’t be blowing our noses on sacred objects, because they are God’s.
- You will notice that when contagious people in the hospital receive Communion, Father brings them Communion individually. He doesn’t gather all the sick people together and have them breathe and sneeze on each other and share a chalice of the Precious Blood.