What is MPACUK Hiding?

I was perusing the MPACUK website and noticed they had a forum, so I went to take a look. Imagine my surprise to discover that some of the forums were hidden to non-members. What's more is that members have to "introduce" themselves to the forum before being able to view those hidden forums.

The two forums I am most interested in are "Current Affairs" and "Islam and Politics", the latter declaring that it is to "discuss...political jihad".

I have emailed MPACUK asking them about why they feel the need to hide these sections from the public. I eagerly await their response.