All sin, in one form or another, is rooted in disobedience to God. Having been made in the image and likeness of God we have been given the great gift of a free will. This free will was given to us so that we could offer ourselves back to God in an act of love that must be a free will offering. When we turn our will away from God to anything else, be it ourselves or some portion of creation, sin enters in.
In this Sunday's Gospel we have the beautiful story of the Annunciation. Here the angel Gabriel comes to Mary to announce that she is to be the mother of the Saviour. We often focus on the fact that Mary bore and gave birth to Jesus. The beauty of her soul, and the sign of her holiness, however is revealed in the words with which she responds: Ecce ancilla Domini, fiat mihi secundum verbum tuum "Behold the handmaid of the Lord; be it done to me according to thy word."
Our own holiness corresponds to how we respond to God's grace and live out our own "Behold the servant of the Lord; be it done to me according to thy word." The parishioners at St. Stanislaus Kostka have decided that they will not live this out but will follow their own will. In defying their bishop they are defying the authority of Jesus Christ Himself as given to the Apostle and handed down to their successors.
This goes beyond a dispute over property. As the legal owners of the property they had no obligation to cede it to the diocese. They could have kept it and turned it into a Polish cultural center. But they have no right to demand that it be recognized as a parish; this is at the sole discretion of the bishop. When they went outside the diocese and hired their own priest this was an act of schism which by their own actions separated them from the Church. For us Catholics the Church is not just an administrative body of believers. It is the sacramental presence of Jesus Christ in the world. To separate ourselves from the Church is to separate ourselves from the Lord Himself.
And here, I would submit, is a major difference between Catholics and Protestants. While a Protestant may well speak of the need to submit to the will of God, there is no test of this. Instead he submits to what is his own judgment of the will of God, which in the end is nothing more than to submit to his own will. Thus the reason that our Lord established a visible church with a personal authority vested in the Apostles which continues today in the bishops.
That is not correct. While the Scriptures provide the ultimate test, most protestant churches require obedience and submission. In the churches which follow the episcopal model (Episcopal, Methodist, Lutheran, to some extent the PCUSA, etc.) it isn't much different than what you see in the Roman Catholic church. In those which follow the Presbyterian form of government (Presbyterian, Reformed, etc.) , authority lies in the Presbyteries and Synods or Assemblies. Even in a congregational church (Baptists, Bible, Congregational), if you 'do your own thing' you are likely to find yourself disfellowshiped or excommunicated.
From the membership vows of one church: "Do you submit yourself to the government and discipline of the Church, and promise to study its purity and peace? "; for the candidate for licesure: "Do you promise to submit yourself, in the Lord, to the government of this Presbytery..."; for candidates for ordination: "Do you promise subjection to your brethren in the Lord".