Was Morrison stating that every 50s Batman adventure was a simulation? What about Kathy Kane Batwoman and Betty Kane Batgirl? Betty Kane had proven to obviously exist due to her appearances prior in comics such as Geoff Johns and Ben Raab's Beast Boy miniseries. Kathy Kane as well turned out to be real when she appeared in the pages of Batman Incorporated.
I thought Batman RIP as a story worked very well, but this plotpoint always bugged me. It also felt unnecessary. Why would Morrison feel he has to explain away the more sillier aspects of Batman's history when things just as goofy happened in the pages of titles such as Superman and Wonder Woman around the same time period?