Given the well-known White supremacism of German culture, such comments are hardly surprising. What she really means is that it has not worked for Whites.
This is more White-Man's voodoo wherein the failings of Whites are blamed on their victims in order to justify their continuing victimhood. There is no desire here to accept others for what they are but to control others and make tyhem in their own image. This is why Whites have the highest divorce rates in the world because they believe that the purpose of marriage is to change - allegedly for the better - the other person. It is really about command and control and fear of spontaneity and intimacy.
Multiculturalism can never work so long as Whites remain so resolutely Institutionally Racist.