Why did world powers try to appease or ignore germany’s and japan’s expansionist policies at first?

America and other countries believed that ignoring or appeasing Germany and Japan would make them stop their hunger for land. First off, everyone kind of just left Japan alone. We didn't agree with what they were doing but we were like what are we gonna do. Then we have Germany who was basically walking into countries and saying that they were his... and no one stopped Hitler so he just conquered all these countries. Neville Chamberlain the British prime minister even signed the Munich pact with Hitler saying that he could have the Sudetenland as long as promised not to invade the rest of Czechoslovakia. (He later went back on his word but hey he's Hitler)