How could a weak League of Nations lead to dictators rising to power and taking land to expand their countries's borders?

The League of Nations was an international organization created in the aftermath of World War I. Many refer to it as the precursor to the United Nations, created in 1949 after World War II, which still exists today. The League of Nations, however, was not as successful. Imagined by United states President Woodrow Wilson, British Prime Minister David Lloyd George, and French Premier Georges Clemenceau, the League of Nations was supposed to be a forum where countries around the world could discuss their problems and work together to form solutions. The impetus for this came from the incredibly deadly and costly World War I, called the "war to end all wars." (For more information of each of the founders—Wilson, George, and Clemenceau— please read the attached article below!)
One of the biggest problems with the League of Nations was that it refused to help out during the 1920s and 1930's when it was needed the most. For example, in 1920, Russia invaded a Persian port to have access to southern waters. This should be a prime issue for the League of Nations to tackle; after all, it was created to mediate disputes and conflicts! Russia, which was not part of the League of Nations, was not reprimanded. When Persia appealed to the League, it got very little response. Part of the reason why the League of Nations failed to act was because it did not think that as a new organization it had the power to start making judgment calls:

Secretary-general Sir Eric Drummond believed that failure was likely to damage the burgeoning organization, so it was best not to insinuate itself into just any dispute.
(history.com; linked below)

In addition to worrying about failure, the League knew that since Russia was not part of its order, they would likely not heed the League's decision, so no decision was made.
The League of Nations did solve some territorial disputes throughout the 1920s, such as one involving Poland, but it failed when tested with larger empires that were not part of its membership, for example, when Japan invaded Manchuria, a region in China, in 1931. China was embroiled in Civil War and did not mobilize a large response to Japan at the time, but the League was tested by this act. Just prior to this invasion, the League worked to pass the Kellogg-Briand Pact of 1928, which essentially stated that countries should not go to war with each other and should instead mediate their differences. Japan's invasion of China in 1931 directly challenged this pact, and when nothing was done, it made the League of Nations seem incapable of solving global conflicts.
In the mid- to late-1930s, when Germany was expanding its territory under German nationalist ideals like lebensraum, still nothing was done. What's worse is that France and Germany, both involved in WWII, were members of the League of Nations! If League of Members nations were ignoring their purpose and duty to the league by declaring war, then the League itself was broken.
The boundaries of the League had been tested throughout the 1930s, and dictators throughout Europe like Adolf Hitler had noticed that the League was powerless to stop his territorial expansion. Knowing that many European countries felt protected by the League of Nations and its pact not to go to war, some dictators took advantage and pushed their territories, knowing they would not be challenged. When Hitler took portions of Czechoslovakia, and the Czech appealed to the British and French, the Westerners did nothing and instead appeased Hitler's territorial expansion. This represented a failure of the League of Nations and continued the escalation toward WWII.
Attached as an image is a political cartoon that represents the powerlessness of the League of Nations. The League of Nations is calling upon its own members to help break up a fight, but the members are at war with themselves.
https://history.state.gov/milestones/1914-1920/league

https://www.history.com/topics/world-war-i/league-of-nations