quite the opposite. Because of the outrageous propoganda that was spewed from all corners in ww1, real atrocities in ww2 were not believed even though its now historical fact and irrefutable. The Katyn massacre was always known to be done by the soviets, but for political reasons the British and American government kept it covered up despite pleas from Polish intelligence on the ground. It was wise at the time to not drive a wedge between the allies and the USSR, lest one war end and start another which came dangerously close to happening at several times.