Thanks, I do understand the framework you're using, and can now say I don't agree with it.
First, one wouldn't say that morality is subjective just because the morality of an entity depends upon its preferences and agency. Even an objective morality would usually apply moral judgments only to entities with preferences and agency.
Second, subjective should mean that Megan's action could considered moral by Fred but not moral by Tom. In other words, the morality is determined by and depends upon someone's mind. In the relative objective morality I've been speaking of, neither Megan, Fred nor Tom gets to decide if Megan's action is moral. The morality of the action is a fact of and determined by the system of Megan, her action, and the context of that action. The morality of her action is something that could be computed by something without a mind, and the morality of her action doesn't depend on the computation actually being done.
I'm not using any framework here, just definitions. The article defined relative and subjective in certain ways in order to classify moral systems, and I've just been relating how the article defines these terms. There's only semantics here, no actual inference.
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.