I've got to remember this one for the next time the RC's complain about all the mean treatment they receive. :-0
To call "sola scriptura" a "superstition" denies the power and intent of the Holy Spirit to speak as God to man through Scripture, denying the very inspiration of Scripture itself.
Either the Holy Spirit speaks through Scripture or He doesn't.
The Holy Spirit speaks through the Church, which produces infallible teachings some of which are contained in the Holy Scripture and some are not. The notion of Sola Scriptura is a superstition because it believes in a supernaturality of an object apart from the inspired men who produce the object.