These are not all the same issue.

I agree that, as a rule, moderators should post something indicating who closed it and why it is being closed. Both for information, a generic "sunshine" rule, and, most importantly, for education. If it were so obvious why a thread needed to be closed, then presumably no one would ever make posts that required that a thread be closed. Therefore, it is an opportunity to make clear what is and is not appropraite. Perhaps the moderator who closed the original thread was in a particular hurry (which is totally understandable), and we'll learn more after they return from a trip or whatever other business they might be attedning to.

However, I 100% support Plato90s' position that discussion about moderation does not belong in the forum itself. We have a number of meta-forums (such as this one) which are places wehre we can talk about the board itself. Were I in Plato's shoes, I would have moved the thread into this forum (or upon seeing that a thread had already been started, closed it with a referral to this thread).

The forums are for the topics of the forums, not the forums themselves. Surely, anyone who is actively interested in how their favorite forum is run can spare the time to pop over here and discuss it.