sounds like another fad, hell I wouldn't be surprised if some people are getting the facebook logo tattooed on themselves just to show us all that facebook is their fucking life. and for that reason only, I support genocide!
Are you sure it's a turned around christian cross? As an example: The old religions from northern Europe, who worshipped Thor, had similar symbols for his hammer. Those look very close to a turned over cross without having anything in common with it.