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.