The us recession in the 1970s was caused by

The US recession in the 1970s was caused by a period of economic stagflation that followed the economic expansion era experienced after WWI.

A stagflation period is chracterized by low economic growth, high unemployment rates and on top, high inflation levels. It is an extremely difficult situation for policymakers, as measures that aim to decrease inflation tend to worsen the low growth and unemployment problems and viceversa.  

so they can differentiate themselves from others as they saw themselves as the superior race. the star was basically a symbol that meant you are a less of a person than i am because of my race. the star was also degrading for those who had to wear it because they were aware of this and the nazis used the notion to make them feel less like a person.