There really is not much truth in that sentence. The FAQ section "Were people aware of the Holocaust during the war?" covers a lot of ground on this topic. While death camps were loosely-kept state secrets, the German public knew from soldiers' letters about massacres of Jews on the Eastern front and were often direct beneficiaries of expropriated Jewish property. There was even wide-spread and often quite open grumbling in 1944 that the Anglo-American bombing campaign was the direct result of the state's murder of Jews.