Robert Gellately, a historian, has recently proven that from 1933 onwards, most Germans knew about euthanasia and the evil evolution towards what ended as the Holocaust.
Hitler wanted them to know. He made newspapers and magazines report his plans for the murder of Jews and the disabled. But the German people still followed with eyes wide open.
Likewise, with eyes wide open, Irish people are increasingly following Sinn Féin, a left-wing fascist party which conjures up far too many sinister comparisons with Germany in 1933.
A pre-general election Irish Times poll showed that 17pc of the ABC1 class, our educated elite, meant to vote for Sinn Féin.
The young took their cue. A recent Behaviour and Attitudes poll showed four out of 10 people between 18-34 supported Sinn Féin.
But our myopic political, media and academic classes, in thrall to nationalism, turn a blind eye to seven striking similarities between Sinn Féin and the early NSDAP.
First, like the Nazi Party, Sinn Féin has a paramilitary wing.
Second, just as Hitler demanded Sudeten Germans be united with a united Germany, so Sinn Féin demands Northern nationalists be returned to a United Ireland.
Third, just as the Nazis made a martyr of the thug Horst Wessel, so Sinn Féin creates a martyrology around sectarian IRA killers, erecting shrines to them in Northern Ireland to provoke their unionist victims.
Fourth, just as Germans turned a blind eye to the bodies of socialists who turned up in the streets, so we turn a blind eye to IRA victims; gardaí, prison officers, and the parents of Paul Quinn.
Fifth, just like the Nazis used a pumped up version of their national past to persuade young students to sing Tomorrow Belongs To Me, Sinn Féin uses our past to inflame tribal hatreds and our children chant Tiocfaidh ár lá.
Sixth, the Nazis set out to deliberately desensitise otherwise decent Germans by publicising their murders of Jews and socialists.
Sinn Féin practises the same process of desensitisation by social media tweets which gloatingly celebrate the massacre of 18 British squaddies at Warrenpoint, Co Down, with a bomb detonated by cowardly killers across the Border - safe in our safe house.
Finally, just as the Nazis hid in German nationalism, SF hides in a self-pitying Irish nationalism, believing we are the Most Oppressed People Ever, as if we never heard of Jews or black slavery...
But the centenaries of 1920, inflamed by one-sided films on RTÉ from which critical voices were excluded, prompted President Higgins to sound a warning about a rising Anglophobia of which any Irish family with English relatives is all too aware.
He said we should be cognisant of "stereotypical depictions" of the British by some of those on the nationalist side.
Kim Bielenberg, in a recent piece in the Irish Independent, noted "the thousands of British people who live here, and the intermingled English and Irish families living across the water, can be forgiven for feelings of discomfort at the tone of many of the public utterances".
Although they are now in denial, three forces - our politicians, our media intellectuals and our green academics with sole access to RTÉ - aggravated our dormant Anglophobia, and thus fed the Sinn Féin vote.
First, politicians like Leo Varadkar used Brexit as cover to court cheap popularity. And, yes, I know the British were being stupid, but a majority voted for Brexit, they are our neighbours and we should have taken them to task in the calm way Micheál Martin repeatedly urged Varadkar to do in the Dáil.
But as Philip Ryan and Niall O'Connor reported in their biography, Leo: A Very Modern Taoiseach, Varadkar and Simon Coveney made a decision as far back July 2017 "to adopt the most hard-line stance possible in relation to the Border".
This explains the inflammatory incident in October 2018 when, at a summit of EU leaders, Leo Varadkar brought along a hard copy of The Irish Times containing a story about the IRA bombing of a Borders custom post. A leak from an Irish political aide did nothing to allay fears about Varadkar's reckless action.
The anonymous aide made the extraordinary suggestion that Mr Johnson and "the Brits" became "a bit friendlier" towards Ireland as a direct result of the dissident attack - an attack which was aimed at killing Northern Irish police!
Even now, Simon Coveney alternately calls on us to "dial back the rhetoric" while using his Montenotte megaphone to fulminate about fisheries - grandstanding that does nothing except add to anti-English sentiment.
The second factor has been the failure of our public intellectuals like Fintan O'Toole and David McWilliams to take a firm stand against Sinn Féin's sinister agenda.
In February 2020, a few days before the General Election, Fintan O'Toole wrote the following words, which I believe will come back to haunt him: "There can be no progressive government in Ireland without Sinn Féin."
Likewise, the day before election polling day, David McWilliams, in a breezy piece for the Financial Times, assured us "a vote for Sinn Féin in the Republic is not, as in Catalonia, an endorsement of narrow-gauge nationalism. Sinn Féin supports the Good Friday Agreement". To which I reply: it does like hell.
Who can doubt such statements gave "permission" to thousands of their self-consciously cool followers to vote Sinn Féin?
The third factor is the takeover of academe by a new generation of "anti-revisionist" (meaning nationalist historians) whose tribal message is no different from the old Christian Brothers. You can see their feverish faces on the endless flow of RTÉ and TG4 documentaries.
Bolstering complacency on the part of our public intellectuals in the face of SF's dictatorial threat, is the untested belief that Sinn Féin will eventually settle down in Government just like Fianna Fáil did.
Last week, Diarmaid Ferriter, one of our leading historians, told Tonight, that the only way to test Sinn Féin's credentials was to put them in government.
Surely, as an historian, he knows the German bourgeoisie felt Hitler would settle down, too? And that Sinn Féiners, toxic with northern tribal hatreds, are nothing like the soft southerners of Fianna Fáil?
Brexit, followed by the excitable 1920 centenary, has reinvigorated a hatred of England that will be even worse in the coming centenary of 1921.
In the past few weeks, some politicians have slowly woken up to the fact that every time you bash the Brits, past or present, without balance, you feed Sinn Féin's vote.
Recently, Leo Varadkar, like an arsonist returning to his roaring bonfire with a small fire extinguisher, tardily told us that during the centenaries "we have lost our way".
Likewise, The Irish Times, a leader in hectoring our neighbours, is belatedly carrying emollient columns with headlines like: 'Are we enjoying the Brit-bashing just a tad too much?' and 'Brexit has emboldened casual anti-Englishness among the Irish.'
Alas, too little, too late.