I have no clue what terminology is needed for facebook-speak but many facebook sites are open to the public for reading. One does not HAVE to log in. It constantly pesters you to, sure, but one can still read the content.
When I click on your link above I get log in required. If I duckduckgo - hearing tracker facebook - I get a facebook page with content. Not your hearing tracker interestingly enough but an open facebook page with its content.
Edit: Oh…hold on…I double checked that hearing tracker facebook search I did where I got content and I can get there. It seems to turn out it is in fact yours. Maybe the problem is your link that you provided.
Hearing Tracker facebook
I’m just not sure it’s your forum-related facebook page.