Social Darwinists believed that government should not help the poor. They believed that people in a society rise or fall economically based on how "fit" they are for economic competition. If people become poor, it is because they are not fit enough. Their poverty should serve as a spur to encourage them to try harder and become better-off.
Roosevelt's New Deal went against this point of view. The New Deal took the position that people were becoming poor due to factors that were not their fault. Therefore, it provided government help to the poor in a way that would not have met with the approval of the Social Darwinists.