The Metal Men as a whole are robots, and each face prejudices about what robots are not supposed to do. It is difficult for any reader not to respond to these characters, especially if the reader feels himself or herself to be an outsider. The Metal Men are also criticized by others for having too much personality. People want them to behave as pure robots, and reject them when they show human traits or emotion. This too is easy for ordinary people to identify with.
Society often demands that ordinary people behave almost like robots, with rigid fixed behavior.
The Metal Men's problems here are an allegory of people's problems with regimentation, dehumanization and conformity. There is an army officer in the background, Col. Casper. He is very similar to the officers in Beast and other monster movies. He is decent, manly, 40ish and always dressed in a spit and polished uniform, just like the army officers in the movies. He and the Army are always completely helpless to defeat the monster however, just as in the films.