That's a really good point, and should not be overlooked. The Apocrypha is certainly honored among Protestants, even if it is not considered canon, and many, many Catholic writings are likewise referenced. It is perhaps a bit unjust to consider Protestants as rejecting the whole of Catholic tradition, because it simply isn't true. But it will never rise to the level of the Book, and those things not proven in the Book, in the Protestant mind, must be rejected.
And therein lies the problem: they hold the same to be true in reverse. That is, if "proven in the Book, in the Protestant mind" it MUST be true, even if it doesn't work...I.e. God doesn't agree and validate it with an action of the Holy Spirit.