I’m not sure what you are getting at, so please explain to me exactly how Pius IX’s warnings don’t apply here.
He’s pretty clear that using John 17 to push the agenda that the Church needs to be united, that it is not united already in the Catholic Church, that the Church is “divided” and that Jesus wants us all to be one (when we are one in the Catholic Church, His Church) is a grave error. Show me how this “John 17 movement”, which Francis praises and prays isn’t just what Pius IX warns us only serves to “destroy the Catholic Faith”.
John 17 is not heretical. It is heretical to use it in such a way to claim that Christ’s Church is not already “one” in the Catholic Church only.
Ever hear of evangelization?
Get with the program!