Quoting 1st century St. Ignatius out of context and connecting it to the "Vicar of Christ" concept is misleading to say the least.
St. Ignatius worked when the Church was nascent and under persecution. In his writings, +Ignatius had to stress the necessity of following all clergy as representatives, as icons of the Lord on earth, not as personified Christ. The Church theology was as yet not clearly defined and, let's not forget, the man was a man of God, but he was no Apostle.
He is known to have said "we ought to regard the bishop as the Lord Himself." First, coming from the Church of Antioch, founded by none other than +Peter himself, it is plain that +Ignatius did not mean only Peter, but all bishops. It is also clear from his life that he did not become a saint for his teaching but for his martyrdom, and that his teaching may have taken liberties that were not uncommon in the nascent Church.
His writings are notorious for being not well thought-through, unorganized, with run-on sentences and often apparently written in haste. Thus he says
"In like manner let all men respect the deacons as Jesus Christ, even as they should respect the bishop as being a type of the Father and the presbyters as the council of God and as the college of Apostles." [my emphases]
This is quite different from the generalization quoted before.
To say that the Pope is "our" Christ on Earth is saying that the Pope and Christ are one and the same! Then the Roman Catholics should have no problems worshiping the Pope, who is then considered "God" on earth, for Christ is God and assuming his Name is blasphemy.
You know, this is interesting because it really brings out the problem you have with our language. We'd regard those two things as equivalent. "For, what I have pardoned, if I have pardoned any thing, for your sakes have I done it in the person of Christ" (2 Cor. 2:10). Similarly we speak of the priest as "alter Christus" (another Christ) because he acts in the person of Christ. I think you are simply overreading our words. We certainly do not mean this: that the Pope and Christ are one and the same! Then the Roman Catholics should have no problems worshiping the Pope, who is then considered "God" on earth. In fact, we say that the Pope "hold[s] upon this earth the place of God Almighty" (Leo XIII, Praeclara Gratulationis), not that he is God Almighty!
Really, no one over here has ever suggested worshiping the Pope as "Christ on earth", so that should give you a real understanding of how we are using these terms...