This can be argued both ways.
On the one hand, WWII can be seen as a war against racism and intolerance. This was particularly true of the war in Europe and American propaganda tended to emphasize the intolerant and evil nature of Hitler’s regime. One can argue that this was somewhat inconsistent with the racism that was still prevalent in the United States at the time. The internment of Japanese-Americans, the Zoot Suit Riots, and the segregation of African Americans, even in the Armed Forces, can be seen as examples of racism that were inconsistent with the idea that the US was fighting racism abroad.
However, the United States was nowhere near as oppressive towards minorities as Germany or even Japan. The US did not kill any racial minorities on a systematic basis. It did not, as the Japanese did in their empire, use people who were seen as racial inferiors as slave labor. The US was clearly more tolerant than its enemies.
Finally, we should note that the true goal of the US overseas was to stop the expansion of authoritarian powers. If we understand that this was the true goal of the war, the war becomes completely consistent with American goals on the home front. The US was not (the post-war Red Scare notwithstanding) anything resembling an authoritarian state. It was a democratic and liberal society, which was very much consistent with the idea of opposing Japanese and German authoritarian and fascist regimes.