I have to disagree with this, Jon.
Yes Sola Scriptura is practiced (by men with conflicting conclusions mind you) but there is an underlying doctrine to support it.
From the article:
The phrase “Scripture alone,” he said, does not mean that it is the singular voice people ought to consult but that the Word of God does have supreme authority
This implies that God’s Word is reduced to Scripture alone. When actually there are Traditions from God which are not written down, and His judgment about matters which are not explicitly addressed are decreed through the Magisterium of His Church.
Scripture, Tradition and Magisterium cannot contradict one another. They all spring from the Word of God.
The Word of God DOES have Supreme authority! Catholics do not necessarily disagree with this.