their fan base and their actions. I was in Germany in 2013 during World Cup qualifying on a NATO mission. We had officers from all over Europe who would talk nonstop about soccer and the upcoming tournament in Brazil...lots of trash talk on all sides.
The German officers generally stayed out of it and didn't want to argue over it. One of them explained to me that since World War II national pride is a touchy subject in Germany. It wasn't until the 2006 World Cup that flag waving was even accepted again.
It was pretty apparent that the Dutch's, Belgian's, and Danes issues with Germany was more about resentment over WWII than anything their soccer fans have done. The Dutch were also angry that Germany defeated them in the 1974 World Cup, a match were the Dutch had the lead after scoring the first goal before a single German even touched the ball.
The Italians had no issues with the Germans, which makes sense as no other country has had such amazing success against them as Italy. The French were, the French. They didn't really get along with anyone. The Spanish certainly didn't have any issues, they were the defending World Cup and Euro winners. Lots of other countries were jealous of Germany's success. To say that German fans are insufferable is a stretch.