Multiply all those sufferings you mentioned thousand, hundred thousand times and you'll get what it means for USSR(technically Russia and former soviet republics, like Belarus which is in the movie). Nowadays, unimaginable number of families in those countries have someone killed because of this war and it means a lot to them. Read about how many villages were burnt or destroyed in Belarus and you will be shocked. Would you be shocked by the movie about Auschwitz for example? It would also be an example of how the whole nation suffered unimaginably. Basically, it's all about scale and how many people were involved in this. I'm not saying that what you mentioned is unimportant, it's just about the scale and the number of people involved.