Why did some americans turn to socialism and communism during this period?

You have not mentioned a period but I think you are referring to the late 19th century and the early 20th century.

When America began to turn into an industrialized nation in the late 1850's, the age what we call now "The gilded age" officially began.

A handful of industrialists, bankers, professionals, and business owners accumulated a massive amount of wealth and in doing so, many working class people were striped of their most basic needs. Working conditions in working places were horrible and many immigrant were faced with many social, economic and justice discrimination.

This is why Communism and socialism got popular in these times as they were addressing the needs and the welfare of the common people.

Explanation:

darwinism is survival of the fittest there for social darwinism is the survival of the wealthiest