The massive resentment of the German populace towards the Treaty of Versailles stemmed from misrepresentations of the Treaty itself as well as the general mood within the country in the immediate lead-up to the Paris Peace Conference. It was the Germans who had appealed to the American President Woodrow Wilson for a ceasefire armistice to the war, and it was thus the German Reichstag (parliament) which believed that the Allies would give them favourable terms of peace and at the very least, give them their due representation within the proceedings of the Paris Peace Conference.

In Germany too, the nation had been led to believe (perhaps erroneously) that they would be heard at the Paris Peace Conference and their own demands would be taken into serious consideration by the Entente Powers or the "Big Four" (British PM David Llyod George, French PM Georges Clemenceau, American President Woodrow Wilson, and Italian President Vittorio Orlando). When it became clear that the Germans would not be involved in the majority of the peace proceedings and instead only be called on to sign the end product, there was national outrage. The following is adapted from a previous response I did on what the experience of the German delegation at Versailles was like:

The delegation was composed of several key figures, all of whom brought some form of political agenda and feelings towards the Treaty. At it's head was Reich Minister for External Affairs Count Ulrich von Brockdorff-Rantzau, Reich Law Minister Dr. Landsberg, Reich Post Minister Johannes Giesberts, Prussian state president Robert Leinert, financial advisor Carl Melchior, and Professor Walter Schueking. All these men had practically the same reaction to the terms when it was presented to them on May 7th, 1919: utter shock and rejection of the Allied terms. Upon receiving the Treaty from French Prime Minister Georges Clemenceau, Brockdorff-Rantzau famously remarked in his speech:

"It is expected from us that we should accept the guilt of War. This statement would be a lie in my mouth."

The problem with the German's position however, meant that the delegation was incapable of altering the Treaty in any way, shape, or form. By not involving the Germans in the peace negotiations or the treaty writing process, the Allied Powers had essentially stripped all chance of getting the Germans to agree to their terms without the torrent of complaints which inevitably followed. Almost immediately after being presented the Treaty, the German delegation began drafting and sending "notes" to the Allied delegations about the impossibility of fulfilling the Treaty conditions, and some included counter-proposals to specific questions. Here are some of them:

• Protest on Reparations: The war reparations which Germany had to pay were crippling to say the least, and what's even more shocking is that no one quite knew how much Germany had to pay when the Conference was concluded. In the end however, Germany offered
• Clause 231 (War Guilt): On May 13th, 1919 the delegation from Germany protested against the "War Guilt Clause", which stated that Germany accepted the responsibility (and hence the blame) for starting the Great War. The German text of this protest actually reads:

"The German people did not will the war and would not have undertaken a war of aggression. They have always remained convinced that this war was for them a defensive war... They cannot consider the former German Government as the party which was solely or chiefly to blame for the war."

• Clemenceau responded to this protest by bringing up a note from November 1918 sent by the previous German government to US Secretary of State Robert Lansing, in which Germany admitted that she was indebted to make reparations on account of "Germany's aggression by land, sea, and air."
• The Germans did agree to the concession of Alsace-Lorraine back to France, but vehemently protested the Treaty's stipulation of giving up the coal mines in the Saar Basin, the East Prussian corridor to a newly-formed Poland, Eupen-Malmedy, Upper Silesia, Prussian Moresnet, and various other German-run districts in what would form Poland.

These are of course, shortened versions and by no means an exhaustive list of the German protests at the Treaty of Versailles. The general experience of the German delegation was one of constant rejection and at times blatant antagonism by the Allied peacemakers. The chaos caused by the peace terms caused so much upheaval back home and in Versailles that Brockdorff-Rantzau left the Paris Peace Conference, and Germany's first democratically elected Chancellor Philipp Sceidemann resigned on June 20th over the Treaty. The Allies pressed the Germans, essentially giving them an "ultimatum" to sign the Treaty or (at least in the minds of the German government) face a renewed invasion of German territory and a continuation of the armed blockade. The new government quickly dispatched Foreign Minister Hermann Mueller and Colonial Minister Johannes Bell to accept the Allied peace terms, and the Diktat von Versailles (Decree of Versailles) was signed by the Germans on June 28th, 1919.

In modern and postwar historiography, historians have pointed out that the Treaty of Versailles was actually rather fair in relative comparison to the Treaty of Sevres, Trianon, and Saint-Germain (which quite literally demanded the dismemberment of Germany's allies in the war, the Austro-Hungarians and the Ottomans). What explains the general mood of resentment which the Germans felt towards it was that they did not view themselves as the guilty party in starting the war, as the official "propaganda" line ran that it had been conducted as a war of national defense against the hostilities of the French and Russian governments surrounding the country. For more on the matter, I have attached an excellent documentary regarding the larger process and difficulties facing the peacemakers in Paris 1919, and a lecture by Margaret MacMillan on the Treaty 100 years after it was signed. Alternatively, consider reading this response I made on the Treaty of Versailles "being overkill" for some foundational knowledge. Hopefully this response helps, and feel free to ask any follow-ups as you see fit.

Sources

Bhattacharya, Swapna. "The German Delegation at the Paris Peace Conference 1919." Proceedings of the Indian History Congress 51 (1990): 724-29. Accessed January 19, 2021. http://www.jstor.org/stable/44148322.

Cline, Catherine Ann. "British Historians and the Treaty of Versailles." Albion: A Quarterly Journal Concerned with British Studies 20, no. 1 (1988): 43-58. Accessed February 20, 2021. https://www.jstor.org/stable/4049797.

Cohen, Bernard Lande. "A Defense of the Peace Treaty." The North American Review 237, no. 5 (1934): 453-61. Accessed February 20, 2021. http://www.jstor.org/stable/25114448.

"GERMAN PROPOSALS AND COUNTER-PROPOSALS." The Advocate of Peace (1894-1920) 81, no. 6 (1919): 189-92. Accessed January 19, 2021. http://www.jstor.org/stable/20668298.

Marks, Sally. "Mistakes and Myths: The Allies, Germany, and the Versailles Treaty, 1918–1921." The Journal of Modern History 85, no. 3 (2013): 632-59. Accessed February 20, 2021. https://www.jstor.org/stable/10.1086/670825.

Weinberg, Gerhard L. "The Defeat of Germany in 1918 and the European Balance of Power." Central European History 2, no. 3 (1969): 248-60. Accessed February 20, 2021. http://www.jstor.org/stable/4545537.

Further Watching

Lecture by Margaret MacMillan. "The Treaty of Versailles: 100 Years Later."

"The Peacemakers" Documentary by the BBC (Margaret MacMillan speaks here too alongside other historians).