The Church, however, has the authority to impose discipline

The Church of Jesus Christ

Nocreo:1123 (First Lateran Council), reaffirmed in 1139 (Second Lateran Council) and 1545-1564 (Council of Trent).

You made the claim so you'll have to prove it. None of those say anything about the Church turning celibacy into a Commandment of God.

It is however, a discipline imposed upon priests by the Church.

Paul was neither priest nor deacon: he was an apostle.

He was Priest and Bishop.
First of all, he accepted the priestly duties which Christ had assigned to him.

Here it is explicit in the original Greek, which loses something in the translation to English:
hierourgeō
1) to minister in the manner of a priest, minister in priestly service
a) of those who defend the sanctity of the law by undergoing a violent death
b) of the preaching of the gospel
Romans 15:16
King James Version (KJV)
16That I should be the minister of Jesus Christ to the Gentiles, ministering (hierourgeo) the gospel of God, that the offering up of the Gentiles might be acceptable, being sanctified by the Holy Ghost.

Second, all the Apostles understood that they held the office of Bishop. This is St. Peter speaking about Judas Iscariot's Bishoprick:
Acts 1:20
King James Version (KJV)
20 For it is written in the book of Psalms, Let his habitation be desolate, and let no man dwell therein: and his bishoprick let another take.

The two are not the same--obviously, considering that Peter is explicitly named in the Bible as being married.

St. Peter was married but St. Paul was not. 

Read the verse right before that: "But I say this of permission, and not by commandment." Paul is giving his personal opinion--advice that he obviously thought was good and valid, but was not a command from God.

Again, I didn't say it was a command from God. So why do you keep bringing up this straw man. 

The Church, however, has the authority to impose discipline upon its members. 

Don't get me wrong--I'm not saying "You're wrong and therefore will go to a very bad place." It would be quite odd of me to make such a statement (I am a non-Christian).

Really? So why do you think you know anything about Christianity?

But there are times when the tradition of the Magisterium has departed from the actual text of the Scriptures.

The Catholic Church has never departed from Scripture. If you are not Christian, why do you care? You don't keep Scripture at all.

They may have felt that they had a valid reason for doing so--

Catholic doctrine is the most Biblical of any religion bar none.

I have "no dog in that fight."

Exactly! 

But for those who hold the scripture as the word of God, and do not hold to the doctrine of papal infallibility, your position is tenuous, at best.

Here is what Scripture has to say:
Matthew 16:18-19
King James Version (KJV)
18 And I say also unto thee, That thou art Peter, and upon this rock I will build my church; and the gates of hell shall not prevail against it.

19 And I will give unto thee the keys of the kingdom of heaven: and whatsoever thou shalt bind on earth shall be bound in heaven: and whatsoever thou shalt loose on earth shall be loosed in heaven.

1. Jesus gave St. Peter his own name. It is Jesus/God, who is the Rock. But Jesus appointed Simon the Rock. Thus signifying that Simon was representing Him before the Church.
2. Jesus gave St. Peter the keys to the Kingdom and said that anything which Peter bound was bound in heaven and anything he released was released in heaven. Thereby saying that Peter was infallible. God would confirm any decision he made.

Now, produce the evidence that you claim invalidates the doctrine of papal infallibility. 

Sincerely,

De Maria