The "revisionists" crawl out of the woodwork again....
The first clue is the blatant error of fact in the first few lines. The scrap of paper that Chamberlain brandished at Heston was not the Munich Agreement and it said nothing about the Sudetenland. It was the Anglo-German Declaration, a side-deal that Chamberlain sprang on Hitler which stated that the British and German peoples wished never to go to war with each other again. The Agreement was a quite different, ruthless diplomatic deal between Britain, France, Germany and Italy that carved up Czechoslovakia, averting a German invasion and preventing a war.
The Anglo-German Declaration was the culmination of Chamberlain's campaign to build a rapport with Hitler which he had pursued since the first autumn of his premiership a year before. He had begun by trying to buy Hitler's friendship by handing him a few million Africans and now thought that three million Sudetens would close the deal. Appeasement became a dirty word because of the way in which Chamberlain and his chief advisor, Sir Horace Wilson, tried to achieve peace not because of their desire for peace.
Chamberlain genuinely believed that he had succeeeded and took the unthinking adulation of the crowds as evidence that he had been right. In reality he failed, just as he failed in every major aspect of diplomacy both before Munich and after. Even after Hitler had demonstrated that neither the Declaration nor the Agreement meant anything to him by seizing the rest of Czechoslovakia six months after, Chamberlain still dreamed that he could prevent war. Chamberlain and Wilson were so desperate to prove to Hitler that the door was still open to a deal that he came to believe that the British leadership would stop at nothing to escape war, even reneging on the guarantee to Poland. Hitler invaded Poland and triggered the Second World War.
Chamberlain weakened Britain's preparations for war. He was sure that war would not come and he pursued a policy which left the RAF saddled with aircraft that were less than useless when they faced combat. All he cared for were the crude totals of aircraft produced that he could deploy against Churchill's criticisms.
Chamberlain was a good minister of health and a competent, if conservative Chancellor of the Exchequer, but no more. He deserves all the blame that has been heaped upon him for his diplomacy.