I think Sam’s point is somewhat similar to the Riaz that I quoted in the Shmuly Yanklowitz thread:
??? ?? ??? ???? ??? ?? ????? ???? ?? ??? ?? ??? ??? ???? ?????? ?????? ??? ?? ????? ??????? ???? ???? ???? ?? ?? ??? ???? ????? ?????? ????? ??? ??? ?????? ???? ???? ???? ????? ?????? ?? ???? ????? ??? ????? ????? ??? ??????? ?????? ?? ??? ?? ????? ??? ??? ?? ??? ?????? ????? ?? ??? ?? ??? ????? ??? ?????? ??? ??? ?? ???? ????? ?? ??? ?? ?????
He is essentially saying that the Rambam can’t make up things that aren’t in the Gemara. Now the Riaz is specifically talking about fundamentals of the religion, so he might not extend it as far as Sam does.