Well, suppose I have to do this as I’m talking about a current TV show - SPOILERS FOLLOW…
As it uses not just their own words, but their actual voice recordings, it’s quite apparent how vulnerable they were and how things that had happened in their family life may have shaped them. It’s easy to understand why they craved the attention - not necessarily of the media btw - in fact I’m not sure they wanted that at all - but just of someone willing to listen to them and care about them. There girls also appear as adults, now, and it’s obvious that one of them at least is still extremely fragile. It’s also totally understandable why Maurice Grosse became so entangled and believed everything they said and wanted to protect them, once you hear his background story. The younger girl, as an adult, recollects how Mr Grosse (as she still refers to him) cared about them and still came to see they were all ok long after everything was over. Also, just to note, contrary to other comments saying the girls admitted they had made it all up - that certainly isn’t what they said then and it isn’t what they are saying now as adults either. Though they don’t really ever clearly state what their explanation for everything was.