I did not say he was an outsider, just that the ritual would likely not be "extremely beautiful" to one, according to Aumann. Certainly a day of rest is generally a good thing, few people disagree. But useful and beautiful are not at all the same thing. His argument, as quoted, was completely backwards from the usual ones ("you have to observe Sabbath if you are Jewish"): "Sabbath ritual is beautiful, but one must be religious to observe it, so I better be religious". Whether he really thought that or not, I do not know.