I think you're right that it's a Truth question, but all questions are Truth questions if you believe in the premise.
The premise of the question is that
Does she preach the basic Christian message of salvation by faith in Jesus alone, as described in John 14:6
If you don't believe that (because you're not a Protestant) then you shouldn't presume to answer that question from your POV. A Catholic would never say that John 14:6 suggests the "basic Christian message of salvation by faith in Jesus alone" because Catholics don't believe in sola-fide.
Therefore, this is not a "Truth Question" as define on the site.
Personally, I think all questions are "Truth Questions" (especially Catholic ones) and it's up to the people who want to close questions to be very careful in analyzing or answering the question to see where the question is coming from.
Basically, "sola-fide adherents" is specific enough for me.