Prior to the nu52, Diana was defnitively made from clay. There were plots that revolved around it (she was de-evolved to clay, Clayface sought her out for her clay, etc.) and the gods responsible publicly acknowledged it. That this is now just a story she was told makes this a hard re-boot (in addition to things like Aleka/other children on Themyscira, sex pirate raids, Hippolyta's hair color, Ares as her patron and not her archnemesis)
This doesn't make the 'shocking moment' meaningless. It just redefines the world of the character as a hard re-boot and not a soft one.