I'm not quite sure how non-Catholics would be expected to know enough about Catholicism to know whether they are questioning authoritative teaching or not.
The same could be said for most Catholics, who have little real education in the teachings of the Church. So what we need to do is advise people to at least study the Catechism before posting on the OBOB forum, or "fact-check" their stuff before they click the "submit reply" button.
When I am in discussions with an orthodox Catholic, I often find them bringing up obscure points or 150 year-old encyclicals that are certainly not common knowledge, even among Catholics (and that leads me to feel skeptical about their accuracy).
Many, but not all, "orthodox" or "traditional" Catholics live (or would like to live) in the Church of some earlier times. For some it is the first half of the 20th century, for others it is the 19th century, and for some it is the Middle Ages. Today's Church and many of the theological ideas and encyclicals of popes from the past 60 years are an abomination to them.
I will give credit to OBOB and other Catholic forums, and the orthodox Catholics who post there, for leading me to learn more about my church. To understand what they were talking about, I had to find and read the documents, papal biographies and histories of the times that they were discussing. I learned about the Syllabus of Errors in the 19th century and attempts to quash "modernist" ideas and trends in the early 20th century. I read about the battle that the church waged (and lost) to retain sovereignty over secular states, and read all or portions of encyclicals by the Pius Popes and others, and learned what the Church has taught about the Bible and tradition, how that teaching has changed (even in my life time) and how it differs from how non-Catholics (and even many Catholics) perceive it.
My knowledge and understanding of many religious terms increased, and I learned what Arianism and Docetism were all about; what it meant to discuss hermeneutics and eschatology; the meaning of hypostases and latria; and what ontological and soteriology referred to.
Mostly I learned that Catholics themselves, including Popes and theologians, have vastly different ideas of what being "Catholic" means. And this is carried over into what being a "Christian" means, as I have been often amazed at the wide range of definitions that people use. That is one reason I use the term "disciple of Jesus" for my religion tag, for to say I am Catholic doesn't say where I am on the spectrum of Catholicism, and even more so with saying I am a Christian.
To forbid discussion and debate on critical issues and ideas is an indication (at least to me) that we are unsure of our position, that we fear questions and new ideas, that we dislike being challenged, that the foundation of our faith is built on sand, not on solid rock. We all know that no church, no person, can force us to accept a belief imposed on us externally. What we believe must be generated internally. Jesus was clear about that, yet the Church assumes it can force belief on people. The image I see the Catholic church projecting from this attitude, to its members and to the world, is of exclusionism, secrecy and fear, bordering on paranoia. It is not an attractive image; it does not adequately and properly reflect on what the Church is really about, and should be about.
The administrators of CF can do what they want with their forums; we are just guests here. They can certainly limit who can post and what they can post in a particular forum. But then I would ask that there be a place for those who are "shut out" to post ideas and hold discussions that are not acceptable on the OBOB forum. Ahh, but that was taken away as well.
The impression one must get from all this is that only certain, acceptable Catholics are welcome here. Very sad.