Since we have those areas on the forum, I would rather not make them only visible to forum members.
That way, a prospective member knows what the forum offers in Topic areas before hand.
And there are members here that often visit the site and read some of the Topic areas or the recent posts that kind of span Topic areas without logging in.
I have done so myself.
And since the recent posts and replies are shown prominently without regard to the Topic area they were posted in hiding ones belonging to a specific Topic area could be a challenge.
If you feel like I do, there are some posts that you would just as soon see drop from sight and were upsetting to us.
To make that happen sooner, one just does not reply to them as replying will keep them in recent posts.