How about posting a 'this thread is closed because of so and so' message when this is done instead of closing them without comment?

A few moderators do this, and even the rude folks at HTF at least post a message and or reason for the thread closing.

Would sure save a lot of 'why was this thread closed' postings and frankly comes off as extremely rude.

I do agree that this sounds like a good idea. Quite often, I hear bits and pieces on other sites about the this thread and that got closed on Mobius. Lots of complaining without any serious thought as to the reasons.
A statement at the end would probably help clarify things and would help in smoothing things over when people get annoyed about it.

Most of the time, I think we do provide some sort of reason, but you're right--we don't all of the time, and I think we can probably make more of an effort to do so. I can tell you right now that we recently closed a thread on the Cult & Exploitation board after my pleadings to not post about pornography were ignored.

Thread closings are "rude?" That's not anyone's intent, and that's assigning unnecessary manufactured drama if there's really a belief that threads are closed to be rude or malicious, because that couldn't be further from the truth. That's mind-boggling. Threads are occasionally closed in moderated forums like ours as a normal course of business when discussions are off-topic -- it really shouldn't be taken offensively. If someone doesn't understand why, they are welcome to email us -- we're glad to offer an explanation, as I believe I've done a time or two for you, Darren. But most questions about thread closures can be easily answered by a fresh read of our posting guidelines instead of requiring moderators to belabor something that's already in black-and-white to publicly justify every decision.

I disagree.

And wouldn't it be easier to close a thread with a pleasant one sentence notification/explanation than to have to answer a bunch of emails asking about it?

Seems like it would save a lot of time and bother.

Plus while the voluminous posting rules may be easily accessible for anyone who wants to read them, all rules can be open to interpretation.

Explaining, albeit briefly the reason for the thread closing at the time would give a much clearer understanding about how the rules are being interpreted AND which ones are being broken.