Devildoc
Verified Military
Honestly, most of the mentorship and SOF specific discussion is on Reddit these days. There it is pretty specific, political discussions are not allowed. Reddit has basically replaced message boards like this for niche topics.
I follow Aaron (Love) and his guys because they just put out cool content. There's a Marine-centric podcast, A to B, that uses a variety of social media. "Forums" like this move at glacial speed compared to some other modes of technology and I am amazed watching these guys manipulate it (not in a bad way). It's like watching a conductor of an orchestra.