Specifically as far as the second part of your question- in this post in which I discussed the decrease in antisemitism in the wake of WWII, I wrote

Why did it decrease so quickly? A large part of it was a greater awareness of bigotry in general, with antisemitism a large part of it but the Jewish community only one beneficiary of a larger campaign against hate. Once the strains of wartime were over and America faced newfound prosperity and peace, more mental energy was given to the possibility of improving the country for its residents. Part of this was due to the many soldiers who had served and, as mentioned above regarding Jewish soldiers, encountered bigotry that soon vanished by necessity under fire- that bigotry was then seen to be as senseless and horrifying as indeed it is. A poll of US soldiers in August 1945 in the army magazine Yank asking what changes soldiers wanted most from their country after the war ended had as its highest scoring result "above everything else, the need for wiping out racial and religious discrimination."

Soldiers were certainly affected by their experiences seeing survivors in the concentration camps, but it seems like the war in general had its own broader impact in terms of its effect on changing soldiers' prejudiced views.