Chamberlain wasn't a pacifist. He responded to Hitler betraying his Czech agreement by forming dozens of defensive agreements and alliances to halt Hitler... and then literally declared a war.
That Sudetenland agreement was actually entirely reasonable. The Germans there wanted to be German and were being abused by the Czech government. The issue is that Hitler annexed the whole thing.
Firts of all he and his French counterpart were the ones who betrayed the Czechoslovakian people in
Munich 1938, that Hitler later swalloed the remains of Czechoslovakia was a direct result of that betrayal, made possible by Chamberlain and Daladier. Also noteworthy is that Poland and also Hungary annexed a part of Czechoslovakia as a result of that agreement.
England, France, Poland and Hungary reaped what they sowed, so to say.
Also a direct result of the inaction of both France and England in Munich was the Ribbentrop-Molotov Pact signed just a few days before the outbreak of the war, which was the reason why Stalin could occupy the Baltic states and the eastern parts of Poland (don't forget Poland was later invaded by both Germany and the Soviets), also just being watched by both the French and the British.
All Chamberlain did was give Poland a guarantee to defend them in case of a German attack, which we all know was just lip service because nothing happened after the declaration of war by England and France.
They left the Polish people behind as they did with the Czechs and Slovaks. There was no noteworthy military action, except minor RAF bombings, before the Wehrmacht attacked in the West in 1940. They did nothing for the Poles, absolutely nothing.
Basically the war really started when Winston Churchill became Prime MInister, the French didn't even played a role anymore at that moment.
Calling the Sudetenland agreement, which was an agreement just made possible because Hitler threatend directly with a military invasion is preposterous, tbh.
Nothing, absolutely nothing, justified the Munich Agreement, which was just possible because both England and France shat their pants being scared to death while the Czechoslovakian Army was ready to put up a fight for the defense of their nation, which given the state the Wehrmacht was in during that time they might even could have won.
The Munich agreement was treason against Czechoslovakia, caused by two nations (FRance and England) paralyzed by fear about a new war in Europe.
Also the fairy tale that German people were opressed by the Czechs, yes the Czechs ruled with a hard hand in said territories after the Czech-Nazis under Henlein caused a major stir up of insurrections. Actions which were directly ordered by Berlin and organised by
Konrad Henlein and his cohorts.
What is important is that all the events before the Munich Agreement like the reinstitution of the Draft in Germany, the open re-armament, the founding of the Luftwaffe and the Wehrmacht re-entering the demilitarized Rhineland were met with decisive inaction by both the French and the English.
The agression against Czechoslovakia and the resulting Munich agreement was made possible because all the inactivity of England and France gave Hitler the illusion he could go on and on with his agressive politics without anykind of interference by both England and France. Sadly he was right in that regard, both England and France only reacted when it was already to late.
Chamberlain (and his predecessors MacDonald and Baldwin) had intelligence information about what was going on in Germany since 1933 and to brutally blunt here, it was a major factor for the heavy losses the British Army and the RAF suffered in the early stages of the war that all three of them did nothing to counter the massive re-armament, they did nothing to bring the RAF and the British Army up to modern standards, nothing.
But to be honest,all of this could have been avoided when the allies after the Great War would have used their brains and wouldn't have followed their thirst for revenge.
The
Treaty of Saint-Germain (between the victors of World War I and Austria) and the
Treaty of Trianon (between the victors of The Great War and Hungary) regulated the new borders of Austria and Hungary, and thus caused devastating political and economic effects.
As a result of these treaties (which were partly even worse than the Treaty of Versailles for Germany) economic difficulties and extremist movements (both communist and fascist) gained strength and there was no regional power in central Europe left to do something against them.