This is a really good post on what's wrong with radical traditionalists.
My beef with traditionalism is how many proclaim fidelity to the Church while not being faithful to the Church.
Ultimately, you either trust in the Church's Magisterium, or you don't.
Magisterial teaching is what the living Magisterium says. Not what you think dead popes said.
Why would the papal Magisterium have been right for 2000 years, but then suddenly go astray?
You shouldn't have to ask whether you have to decide between the Magisterium and one's personal evaluation of Magisterial teaching.
God established the Magisterium to eliminate all that second guessing.