If I understand you correctly this is my interpretation as well. But to clarify: there doesn't even have to be an agent in the judgment itself. Take the proposed judgment: "Black holes are immoral". This can either be subjective or objective. You are an objectivist if you look to something other than a mind to determine it's truth value. If you think the fact about whether or not black holes are immoral can be found by looking at the universe or examining black holes, you're an objectivist. If you ask "How do I feel about black holes", "How does my society feel about black holes" or "How does God feel about black holes" you are a subjectivist because to determine whether or not to accede to a judgment you examine a mind of minds.
Edit: I just read byrnema's comment and now I think I probably don't agree with you. You could also be an objectivist or subjectivist about a judgement of a purely mental fact.
Objectivist: Jealousy is immoral because it was written onto the side all quarks.
Subjectivist: Jealousy is immoral because I don't like jealousy.
I agree with everything in your first paragraph, and was amazed it wasn't addressed to me. I can't believe how complicated this turns out being due to semantics. We could really use a good systemizer in the whole morality field, to clear the confusion of these tortuously ambiguous terms. (I should add that I'm not aware that there isn't one, but just skimming through this thread and its sisters seems to indicate one is needed.)
Less Wrong is extremely intimidating to newcomers and as pointed out by Academian something that would help is a document in FAQ form intended for newcomers. Later we can decide how to best deliver that document to new Less Wrongers, but for now we can edit the existing (narrow) FAQ to make the site less scary and the standards more evident.
Go ahead and make bold edits to the FAQ wiki page or use this post to discuss possible FAQs and answers in agonizing detail.