The Horrors Weren't Common Knowledge Yet

I don't care how many times I've seen this, it always makes me sit back and remember that the soldiers on the other side are just people born in a different country. They're likely fighting for the same reasons we are. (Excluding extremists obviously)

My grandfather was conscripted to fight for Germany in WWII when he was 16 and had a complete breakdown when he found out what the people he'd been fighting for had done

Makes you wonder what we don't know about

There's a theory that Germany lost the war because of Hitler's fanaticism. Several of his top generals and diplomats either tried to kill him or flat out quit after a while. The fanatics were mostly confined to the SS, which Hitler wanted to use as the regular army in the waning months of the war.

"Naturally, the common people don't want war; neither in Russia nor in England nor in America, nor for that matter in Germany. That is understood. But, after all, it is the leaders of the country who determine the policy and it is always a simple matter to drag the people along, whether it is a democracy or a fascist dictatorship or a Parliament or a Communist dictatorship. ... the people can always be brought to the bidding of the leaders. That is easy. All you have to do is tell them they are being attacked and denounce the pacifists for lack of patriotism and exposing the country to danger. It works the same way in any country."

It scares me how young some of them look.

Two books that do a good job of discussing the psychology of how a relatively normal culture can commit atrocities are The Nazi Conscience and The Roots of Evil. (Claudia Koontz and Ervin Straub, respectively )

The famous videos of bodies being pushed into pitts with bulldozers was shot by the British after Russian forces 'liberated' the eastern front. The most damning evidence that anything terrible happened was orchestrated by the allies.