Then why do you appeal to tradition and extra Biblical writings so much?
I do not appeal to traditions or extra-biblical writings to argue with the Protestants about the errors of Protestantism. I also do not refer to anythign other than the scripture whe arguing about Catohlic doctrines that are adequeately present in the srcipture.
When someone asks me about a Catholic doctrine that is poorly supported by the scripture, I begin by admitting the fact that it is poorly supported. I then proceed clarifying the doctrine using the material that speaks to the doctrine.