What were the real factors that led to the discreditation of Appeasement as a policy for foreign diplomacy?

Appeasement was one of the most important causes of WWII. Today people say that it was Chamberlain's appeasement that started the war. It is true to some extent because Chamberlain couldn't prevent the war. However, Chamberlain had actually began thinking to change his policy after the Munich agreement; he was forced to change his appeasement policy because many events happened in 1938-1939. Let's see how the events affected Chamberlain's Policy:
Events in Europe pressured Chamberlain to abandon appeasement. For example, Franco's victory in Spanish Civil War in February 28th, 1939 and Mus…