Contemporaries did often denounce anti-appeasement politicians as “dangerous warmongers,” and Churchill himself told the Commons in 1938 that the word “war” had come to be used only by people who would qualify for a lunatic asylum. But the broader historical picture is less extreme: the Churchill Archives Centre describes Churchill in the 1930s as a “Colonel Blimp” figure seen as out of touch and seriously unreliable, not as someone generally regarded as mad. So the claim captures the hostile reception, but “considered mad” overstates it. Sources: Patrick Finney et al./*When Right Makes Might* (Library of Congress PDF) https://tile.loc.gov/storage-services/master/gdc/gdcebookspublic/20/18/01/75/39/2018017539/2018017539.pdf; International Churchill Society, “The Munich Agreement” https://winstonchurchill.org/resources/speeches/1930-1938-the-wilderness/the-munich-agreement/; Churchill Archives Centre, “Churchill’s reputation in the 1930s” https://archives.chu.cam.ac.uk/education/churchill-era/exercises/appeasement/churchill-rearmament-and-appeasement/churchills-reputation-1930s/