"Hence we may easily conclude in what sense Paul uses these words. The reason why the Church is called the pillar of truth is, that she defends and spreads it by her agency...For the same reason, also, she is called the pillar of truth; because the office of administering doctrine, which God hath placed in her hands, is the only instrument of preserving the truth, that it may not perish from the remembrance of men." -- John Calvin
"The pillar and ground of the truth. The church is the pillar and support of the truth because it preaches it to the world, preserves it, and transmits it from generation to generation." -- B.W. Johnson
"The Church, or congregation of believers, which before was regarded as the habitation of God, is now, from a different point of view, regarded as the pillar upholding the truth." ---Robert Jamieson
"The church is the house of God; he dwells there. The church holds forth the Scripture and the doctrine of Christ, as a pillar holds forth a proclamation." --- Matthew Henry
"The figure here is evidently taken from architecture, as the use of the word pillar is. The proper meaning of the one expression would be, that truth is supported by the church, as an edifice is by a pillar; of the other, that the truth rests on the church, as a house does on its foundation. It is that which makes it fixed, stable, permanent; that on which it securely stands amidst storms and tempests; that which renders it firm when systems of error are swept away as a house that is built on the sand. Comp. See Barnes "Mt 7:24"; Mt 7:25-27. The meaning then is, that the stability of the truth on earth is dependent on the church. It is owing to the fact that the church is itself founded on a rock, that the gates of hell cannot prevail against it, that no storms of persecution can overthrow it, that the truth is preserved from age to age>" --- Barnes New Testament Notes
All of these Protestant commentaries are found at the Calvin College website.
Yes, I would like to talk to a Greek scholar as well. A conviction of what the Greek says there certainly be extremely helpful. The preponderance of English versions as well as a cursory glance at the Greek seem to certainly allow for God as the foundation.
Certainly the scripture is self-interpreting on the issue of the sinfulness of mankind which was my original point. The idea of the sinfulness of all (excepting Christ) is consistent throughout the Bible.