Boy, I guess we humans are the most dirteist, sinful, unworthy, irreverant creations that God has made. We can’t touch, say or do anything. So, why did God make us?
The reality is that we are certainly sinful, but that is not really why the Church has traditionally, and as was explained below still does, prohibited the laity from touching the Sacred vessels, the tabernacle, and other sacred items. If it were, then no laymen could
ever touch these items, for they would always carry the burden of sin.
Consider Original Sin. As you may well be aware, the Catholic doctrine of original sin - as opposed to most Protestant doctrines of it - does not refer to the actual personal guilt of a newborn infant as though he or she deserves punishment. Rather, it means that newborn infants are born altogether natural - without any provision of Grace. A newborn is not deserving of punishment - surely not, for it has done no crime! - but it is not capable of Heavenly beatitude either, for it posesses no Grace.
Imagine taking the chalice from Mass, and using it for some beer during a football game. Certainly, you would recognize the problem with that, as would most anyone. The chalice is a sacred item, and the football game and beer - while not evil - are normal, everyday things. They have no holiness to them at all. It would be entirely inappropriate to profane the chalice by using it in such a manner. Now even the angels, in and of themselves, would profane the Lord by being in His presence infinitely more than the presence of the football and beer profanes the chalice. It is thanks to the Lord’s gift of Grace to the angels that they themselves are holy, and so may rightly be in His presence.
As human beings, we are not dirty, vile, terrible things. However, we do not begin to approach the infinite holiness of God. Thus, we do not touch sacred items without cause. Priests hands are annointed when they are ordained, so that their hands may be made holy. It is thus that they may freely touch the Sacred items. God lifts them far above what they are by nature so that they may serve at His altar. Laypeople have not been thus annointed. We are not terrible, vile worms, but we are not infinitely holy, either. Thus, it is not intrinsically wrong for us to touch the Sacred vessels, and with good reason and in the proper context we may do so. However, it is most fitting that we do not approach these items ourselves, for our hands have not been annointed in a special way for the purpose of doing so.
I hope that helps,
Peace and God bless!