As you correctly say and as this article correctly says, the Holy Father did explain these reasons in his book. He has also given Communion in the hand at other masses. From the little that I have been able to observe at a distance, he uses the kneeler and communion on the tongue at big celebrations for the reasons that he states in the interview.
In smaller gatherings where he is celebrating mass for a small group, he does allow the person to choose.
This makes perfect sense, if you have ever been to mass at St. Peter’s. It’s a circus. The mass is still the mass. It’s beautiful and reverent. But having studied in Rome and having attended many masses at St. Peter’s I am no longer surprised at some of the nutty things that people do. For some people, going to mass celebrated be the pope is an event instead of a mass. I will never forget the hundreds of tourists who attend mass at St. Peter’s on Christmas Eve and the Easter Vigil who seem not to have a clue what a mass is, but it’s one of those things that you do if you’re on vacation in Rome during Christmas or Easter. You get tickets and go to “the pope’s mass” as if it were different from the mass in your local parish. People are strange. What can we say?
But we still have to love them.
Fraternally,
Br. JR, OSF