According to the neutrality act of 1939, what was required of nations at war in order to buy arms and other supplies from the united states?

Hee the american public did not truly take in the horror of adolf hitler's regime until years after the existence of concentration camps was first reported in american newspapers. partly this was the fault of the media, which did not give prominent placement to news of the holocaust. what other factors do you think contributed to the long delay in understanding the holocaust?