There is a great deal of complexity in the 1950s' social fabric. One of the most telling points here would be the very idea that there was a definable fear of "the other." Society was structured so that individuals pursue an external end of happiness. Part of this involved not integrating "the other," and being afraid of it. I think that in this, one can see how groups like Hispanics, Asian- Americans, and Native Americans were seen. They represented this "other" for which there was fear and immediate rejection.
The social theory of the 1950s involved a construction of social happiness that was not inclusive. It did not seek to appropriate as many people as possible into its own schema. Rather, it was isolating, seeking to reach a level of external happiness that sacrificed many in its pursuit. In this, groups that were silenced were seen as extraneous to that pursuit. Those who did not fit into the socially conformist pursuit of happiness were not understood. They were not seen as important and became moved to the margins of a society that failed to understand if it, in its own existential state, was working towards a vision or whether it was working them.