I've watched dozens of full scale pilots trying to fly RC over the years, and I can tell you for a 100% fact that it's more difficult for them to fly RC. Why?? Simple. Perspective. Their perspective is different.
I doubt that being a full scale pilot actually makes it more difficult to fly RC. It probably doesn't make it easier, but it seems unlikely a full scale pilot would actually have a *harder* time learning to fly RC. Most of us drive full scale cars --- does this make driving an RC car harder for those of us who have a driving licence?