From what I've read elsewhere the Vatican is tired of people wasting the churches time by reporting instances they think are supernatural and wanting investigations. They blame the internet for this and so they had to put their foot down and tell the churches to stop taking time away from other duties to focus on "supernatural" pursuits.

So this is their rules of what they consider worthy of the church's involvement and if it doesn't fall into these guidelines tell 'em to call Ghostbusters.