It seems that there is an equivocation over the word “contingent” here. @structureoftruth is arguing that he has independent arguments (written on his blog) which establish the existence of God and his attributes necessarily. Now, it is true that we don’t know if these arguments are successful and sound. We haven’t had a chance to discuss them. However, that the soundness of Matt’s arguments are unclear and that Matt’s Euthyphro defense depends on them does not mean that the latter only applies to contingent moral truths.
To take an analogy, we know that if the abc conjecture is true, it necessarily implies the truth of Fermat’s Last Theorem. Now, we currently don’t know if the conjecture is true or not. It’s an open problem. But that doesn’t then imply that the logical link between Fermat’s Last Theorem and the abc conjecture becomes only a contingent link. Our current, contingent, deficient state of knowledge doesn’t change the necessity of the logical link between the abc conjecture and the FLT.
This comes back to what I said earlier, namely that it seems that both participants have different assumptions coming into the debate. Matt seems to be coming into it assuming he is allowed to assume a host of separate propositions and arguments regarding God and morality. (This is like being allowed to assume for the sake of argument that the abc conjecture is true, and only striving to prove that it necessarily implies FLT is true.) However, Faizal is not convinced by the truth of these independent propositions and thus sees no way out of Euthyphro. Thus the debate has come to a stalemate.