I agree with vallinder's point, and would also like to add that arguments for moral realism which aren't theistic or contractarian in nature typically appeal to moral intuitions. Thus, instead of providing positive arguments for realism, they at best merely show that arguments for the unreliability of realists' intuitions are unsound. (For example, IIRC, Russ Shafer-Landau in this book tries to use a parity argument between moral and logical intuitions, so that arguments against the former would have to also apply to the latter.) But clearly this is an essentially defensive maneuver which poses no threat to the orthogonality thesis (even if motivational judgment internalism is true), because the latter works just as well when you substitute "moral intuition" for "goal."