“Germany opened negotiations based upon the 14 points”: Again!!!! Germany opened negotiation hoping it would be based on the 14 points perhaps.
From where, if they did, did they get this? Especially after the rejection by Germany of US mediation in 1916.
On the quantity of Peace talks, not at one moment, Germany showed the will to give-up its war goals…
In Spring 1918, Germany refused the US conditions in The Hague.

Did at one moment Clemenceau or David Lloyd George or Vittorio Orlando, gave the hint these 14 Points were the base for Peace Talks?

“You can say that the Germans were stupid or that the Entente was duplicitous and both would be correct.”: The German had no choice, the Entente was not prepared to give to Germany any choice.
I still don’t see where the Entente was duplicitous as Wilson represented only at best, USA…

“You have a choice. You can condemn the German reaction, because they were actually not promised anything. Or you can say it was a stab in the back because the Germans were duped.”
Sorry, I don’t follow you there.
Fact: Germany and Allies were defeated.
Fact: When winner, Germany imposed Diktat and Occupation Troops on the looser.
Fact: All previous Peace Talks were rejected by Germany when not favorable to Germany. At no moment, Imperial Germany showed a hint of regret for the aggression.
Fact: Facing a military collapse, a succession of Allies surrenders, a mutiny in the fleet, famines and unrest in the society, the German Hight Command and the Junkers decided to pass the buck to somebody else.
Fact: The somebody else had nothing left to negotiate excepted to play the Red Containment Card.

Yes, the German hoped that they could avoid to face the consequences of the Kaiser’s choices to back-up Austrian’s Aggression against Serbia.
Yes, the Entente could have adopted Louis’ Plan and Germany wouldn’t had to face the consequences a lost war.
The stab in the back came from the Junkers and the Political-Militaro Elite which lead Germany in the WW1 and were defeated.
To get invaded countries (having this toll of casualties –1,600.000 young men dead, 5,000,000 injured for France alone) to be as lenient as the Treaty was and then complain about it, even now, is beyond me.
Yes, the German should have expected far worst than what happened. They should have expected what happened in 1945. Or what Germany imposed to France in 1870 (for no damage to German territory and far less casualties) or Russia. Or what Germany intended to impose if winner to the Entente…
The only “stab in the back” was in the German mind. This was for political motives played on German hurt pride.
It back fired badly.
So instead to recognise it, better to blame Versailles than the gloomy, dark, nauseous but entirely German post WW1 political blaming game.

“Or maybe the victims were the German People”: They were. But not of the Entente.

In France, some complained that Versailles was to lenient, that it will open the doors to the renewal of German Imperialism…
So books written at the Period are not the good bench marks.

The reality is:
Germany didn’t paid the compensation
Germany was not under permanent occupation.
Germany was not enslaved.

In fact, Versailles was not implemented…