There are at least three ways in which this statement is true.
First, the total mobilization required women to go to work in a variety of jobs that had previously been male-dominated. Most of these women had to give their jobs up when the men came back from war, but habits changed to some degree. Many of these women, and their daughters or younger sisters, became part of the generation that pushed for a change in the status of women in the US.
Second, the total mobilization required more participation from African Americans. They were in the Armed Forces and they moved out of the South to take jobs in war production. Both of these facts helped to lead to the Civil Rights Movement in the decade or so after the end of the war.
Finally, the broadest change was caused by the mass mixing of society that came about due to the war. Men of all sorts (all classes, all backgrounds) served in the war and were rewarded with the GI Bill. The GI Bill vastly increased the number of people going to college. This helped to remake the US as a country with a well-educated, white-collar workforce.