Jim, the 'your comment is awaiting moderation' message always comes up at Scribblers when there is more than one link in a comment, for some reason. It's annoying the first few times, but once your realize it, you just respond to your own message with any added links, but always only one per post.
Occasionally there are other problems there, and yes, he will occasionally ban or put people on a tighter leash for a while. But generally it's a pretty open site.
On the Guardian thing, yeah, I think sites don't take well to people posting things that were posted elsewhere. I can imagine various reasons why they might want to do this, but it would just be speculations on my part.