He has not stopped complaining in the public forum since June 30 when Pope Francis personally informed the sixty-nine-year-old cardinal that he would not be retained as prefect of the Congregation for the Doctrine of the Faith (CDF).
Recall how he immediately leaked the news of his dismissal to friends in the media  even before the Holy See Press Office officially announced it the next day.
It was the reaction of a stunned and angry man.
One can sympathize. Not a single cardinal who has headed this 475-year-old office— formerly called the Supreme Sacred Congregation of the Roman and Universal Inquisition (and later the Holy Office)—has ever been let go so unceremoniously.
The pope did not publicly thank or acknowledge Müller for his five years of service; just let him go six years before the canonical retirement age. The cardinal claims he had no clue whatsoever that Francis was going to cashier him, even though almost everyone else saw it coming.
No clue, indeed. And apparently poor Cardinal Müller still hasn’t got one.
As Christa Pongratz-Lippitt—LCI special correspondent on church affairs in the German-speaking lands—has been chronicling, he keeps digging himself a bigger hole each time he gives another public interview. 
The news agency Deutsche Presse Agentur (dpa) published one on Wednesday in which the cardinal even digs into Francis, insinuating that the Jesuit pontiff is allowing a papal personality cult to fester while surrounding himself with sycophants.
To be fair, the criticisms are veiled, but only slightly. Müller employs all the subtlety of a Schlittenhammer. (That’s “sledgehammer” auf Deutsch, by the way.)
If this is the sort of stuff the cardinal is telling us publicly, one can only wonder what he’s saying to others privately.
As of this writing, his most recent appearance in the spotlight was Friday in Italy’s leading socially and politically neo-conservative daily, Il Foglio. 
The interview can be described as the self-defense of a man who believes his talents were overlooked and who was shafted for no clear reason.
“I’ve fulfilled all my duties—even more than required,” he said, pointing out that he tried to offer Francis the essential “theological counsel” on which a pope relies in order to ensure “the orthodoxy of the Church.”
It is clear that Müller believes the pope rejected his assistance. Thus he argues on.
“No one ever doubted my theological credentials,” the cardinal said.
“I have always been loyal to the pope, as is required of our Catholic faith and ecclesiology. This loyalty has always been accompanied by theological competence, and so it has never been about a loyalty reduced to pure adulation,” Müller insisted
It’s an interesting and revealing remark because later in the interview with Il Foglio, when quizzed about the differences between his classically restricted view of communion for the divorced and remarried compared to the more open stance of Cardinal Christoph Schönborn of Vienna (which is aligned with the pope’s), Müller said:
“Maybe Cardinal Schönborn has a viewpoint opposed to mine, or maybe it’s opposed to what he himself once thought, seeing that he’s changed his position.”
(So much for John Henry Newman’s adage, “To live is to change, and to be perfect is to have changed often.”)
Some have said Pope Francis was not pleased with the high profile Cardinal Müller carved out for himself in the media through endless interviews and public lectures.
“I think I can say the media presence of Cardinal Ratzinger (when he was CDF prefect) was pretty evident… This is part of the prefect’s job, that it not be purely and simply bureaucratic work,” he said
But he could not stop there.
“Anyway, I was well known before (becoming CDF prefect) as a theologian because of my many writings. And, in any case, it seems to me that even the pope gives interviews,” he said.
Has your jaw dropped yet? It gets better. Or worse.
“The faith, the Church, and the bishops are not affirmed by the applause of the uninformed masses,” Cardinal Müller went on to say.
It’s another curious declaration, given that most people, with the exclusion of political conservatives and doctrinal rigorists, have generally praised the more flexible and less rigid positions that the pope and bishops like Christoph Schönborn, Karl Lehman, Walter Kasper, and Reinhard Marx have publicly offered to the “uninformed masses.”
Yes, Müller criticized all the men mentioned above in one way or another in this new Italian interview.
“Today they speak about responsibility for culture and the environment?” he asked rhetorically. “Ok, but there are many lay people competent in these areas,” he said.
He claimed these were political matters that were not the responsibility of bishops.
Clearly, Cardinal Müller is not too thrilled with Laudato si’, the current Bishop of Rome’s encyclical on care of the creation. But he seems to have forgotten that Benedict XVI—and the cardinal, as well—have also used their episcopal office to try to influence a whole other range of social, cultural, and political topics.
Which brings us to another issue: the now-retired Benedict and the role he continues to play in the life of the Church.
Müller revealed in last Wednesday’s interview with dpa that the former pope was “disappointed” that Francis had not renewed the cardinal’s mandate as CDF prefect.
Why did the cardinal make this public? He had to know that it would only intensify the narrative that Benedict and his allies are part of an opposition, loyal or otherwise, to Pope Francis.
It was bad enough that on July 6 he gave another interview to a German paper  revealing that Cardinal Joachim Meisner, just two days earlier, had also voiced alarm at the ex-prefect’s dismissal.
“It moved and hurt him personally. He thought it would harm the Church”—said Müller—“that naturally speaks for me, but it’s a fact, that was the way he expressed it.”
Meisner died later that night. But we then discovered that it was not the only conversation that the former Archbishop of Cologne had that evening with a leading church figure.
It so happened that Benedict XVI also spoke with Meisner that same evening. This was revealed in a message the ex-pope sent with his personal secretary, Archbishop Georg Gänswein, for Meisner’s funeral on July 15.
Leaving aside the attempts some have made to politicize the content of the message, one is left a bit confused over how Benedict’s description of Meisner’s mood and disposition on the eve of his death was in such contrast to Müller’s account.
The former pope portrayed someone very different from the “disappointed” and worried man Müller spoke to the same evening.
“What struck me particularly in the last conversations with the cardinal, now gone home, was the natural cheerfulness, the inner peace, and the assurance he had found,” wrote Benedict in his eulogy.
Was it a mere coincidence that both Benedict and Cardinal Müller were on the phone to Meisner—who was away on vacation—on the very same evening?
The eighty-three-year-old Meisner had some minor health issues, but he was not a dying man. His death was sudden and unexpected.
The main subject of the triangular conversation most likely was Müller’s dismissal, though it has not been revealed who initiated it. Did Müller first call Meisner to complain about being let go and then did Meisner call Benedict afterwards to continue to discuss this “worrying” situation?
And how many other bishops or church personalities sympathetic towards Müller placed calls that night—or in the days before and afterwards—to the refurbished monastery in the Vatican Gardens where the former pope now resides?
It is understandable that people closer to the thinking and style of Pope Francis and some who are more aligned with Benedict are eager to dispel any talk of opposition between the two men. But there is no denying that the former pope has become the central figure and rallying point for those who are deeply uncomfortable with and critical of the current pontificate.
Benedict is not necessarily to blame for this. And he is certainly not its architect.
But someone has to put a stop to his well-known open-door policy, which Archbishop Gänswein generously extends to political conservatives, Catholic ultra-traditionalists, and others for whom Francis is “not everyone’s darling.”
Or maybe the former pope should at least follow his successor’s example and put a sign outside his door that reads, “No whining!”