Actually, the way I had read it before all the peirushim were posted was that BMYer and Mod 29 wrote something that could have sounded like they meant that no soap is allowed on Shabbos. I realize that they did not say that, but one could have understood them that way, as LB apparently did based on her question.
One certainly could have understood that there are those who hold that all soap is assur (which I thought was the case, since I know people who don’t use any soap on Shabbos, although perhaps, they just don’t feel like watering it down.) In any case, BMyer’s post could have been understood in either of these ways. LB apparently understood it that way, so she asked “how can one wash his hands on Shabbos if all soap is assur (or if one holds that all soap is assur)?”
So Joseph answered that if someone holds that all soap is assur, he uses water. I have known many people who did just that, so I saw no reason to assume that Joseph meant anything else.
Joe, how did I do? And who did better – me or WTP?