As with Scripture, the issue with Tradition is its interpretation and application,
And we have over 1,900 years where Tradition has ALREADY been interpreted (by papal authority) and applied (by papal authority). When Stubborn says that "Tradition is the rule of Faith" he means PREVIOUS MAGISTERIAL AUTHORITATIVE TEACHINGS. In other words, there are 7 sacraments...this is known from Tradition because Scripture does not tell us the #. It's been confirmed from the earliest of Apostolic times that such is the case, and confirmed multiple times by many popes. Thus, this is infallible Tradition.
Why is this concept so hard for you to understand?
and there's only one authority permitted to interpret Tradition, the living Magisterium.
And such prior magisteriums of Church history have ALREADY decided the VAST majority of questions of our Faith. These previously decided truths become part of "Tradition".
As St. Thomas said, by rejecting the Magisterium as the proximate rule for interpretation, you effectively make yourself the rule.
That's not Stubborn's argument.
You replace the Magisterium with your own private judgment. If Stubborn decides something is Traditional, then it's Traditional. This effectively makes you your own doctrinal authority.
How many times has EENS been defined? 3x? Even after the first time, this doctrinal statement becomes part of "Tradition" because EENS has roots in Scripture and Apostolic Tradition. When the Church magisterially defines it again, as a revealed truth, as part of Scripture/Tradition then it becomes (to use a general term) "Traditional" because it is "of Tradition".
Tradition/Traditional simply means "has always been held" or "always taught". When the Church defined EENS, She is saying this is a Divine Truth, which is from Apostolic times (or further back, as part of Scripture). Thus, it is correct to say EENS is part of Tradition. Thus, it can never be changed. Thus, we can point to something novel and decide if it's right or wrong, because EENS has already been decided and is fixed.