What is it?
As most people know the 1930's was a very tough time for the Jews; Between Hitler and because of Hitler shortages on jobs, food, etc. The Jews also lost all of their rights! The Jews were captured, and treated to an unbearable extinct. So, on November 9th, 1938, Nazi troops broke into Jewish houses and beat/killed the Jews inside of the house. They destroyed everything, including their synagogues which were the churches the Jews attended. Kristallnacht means "Night of the Broken Glass". This name represents the houses being broken into on that awful night in history. Today Krystallnacht is celebrated on November 9th - November 10th.
So, why should more people celebrate?
First of all, so many lives were taken away for no reason at all. People at the time in some places believed that this was the right thing to do because of false reasoning. Also, this matters so much to other people, just like some people don't celebrate some of the holidays you celebrate, you like it when they are happy for you. So some of the people celebrating this would be too! You might also want to consider celebrating to show that you care about what had happened and it wasn't the right thing to do.