In effect, the Lutheran claim is a claim of the right to rebel against the teaching authority of the Church, on the grounds that the Church is apostate. Unfortunately, the sole witness for the apostasy of the Church is an alleged disagreement between Church teachings and the scriptures on which the Church relies for those teachings. But the sole witness for the validity, canonicity, historicity, and divinity those selfsame scriptures is the authority of the Church whose members wrote them, gathered, sanctified, protected, promulgated and canonized them.
Disregarding the fact that Roman Catholics were not the only ones who “wrote…, gathered, sanctified, protected, promulgated and canonized” scripture, and disregarding the fact that the Holy Spirit bears witness to the “validity, canonicity, historicity, and divinity those selfsame scriptures,” his premise itself is rather strange:
If a man tells you a map is accurate, and then leads you the opposite way from the direction indicated by the map, would you not assume that he either 1) cannot read the map or 2) is purposely leading you astray? If when you say something about it, he angrily replies “The only reason you have to believe this map is accurate is because I told you, so just trust me” would it not strengthen your belief? If the more you look at the map, the more you see how it matches the terrain, and you are still being led away from where the map indicates your destination, would you not become less inclined to follow your guide?