User blog comment:Crazylittlefreakgirl/Fairy Tail Official Pairings?/@comment-5144306-20120528180752

Like point 1 suggests, it's more of a collaboration between Mashima and the anime staff. I doubt he's actually doing the scriptwriting, otherwise he'd be credited as appropriate. There was one piece of info floating around tumblr a few months back saying that the filler arc would be based on an idea of Mashima's (although, like the info above, there's no credible source for that). But even if he's not writing the arc word for word, does not mean that it isn't canon. Now that Zenotopia has been referenced in the manga it can be considered as canon. The same goes for the movie and the light novel. While not written by Mashima himself this filler arc, the movie and the light novel all have his influence or stamp of approval, and are therefore apart of the canon continuity. The fandom is just ridiculously using the arc to start a ship war.