We should be mourning

I have studied books about the  history of Germany ,The holocaust and what follows.One writer  asks if it even POSSIBLE  for the Jews to grieve the destruction of European Jewry ans the destruction of Yiddish as a common language.Inability to grieve leads to paranoia.
I am asking, is it  not the duty of  us in Europe to mourn  our loss too  and our destructiveness?For who needed WW1?Who began  it?Why? Was it neccessary?
I think not.
We lost also gypsies,disabled children,homosexuals and political   people who  attempted to change what was going on.
And why did Churchill bomb  innocent Dresden but not  the railway lines taking Jews and others to the Death Camps?
Why do we have no shame?