You can read about why Jews now want to be German citizens here:
The short answer to the question in the title of my blog post is this:
Jewish children sent to England now want to go back to Germany because Britain wants out of the European Union
You can read here about why American Jews want to become German citizens:
The following quote is from the news article, cited above:
Joost Oppenheim came into the world stateless.
He had no choice: Born in the Netherlands to refugees from Nazi Germany, both the country of his birth and the country of his ancestry refused him citizenship.
Eighty-one years later, Oppenheim and his family have a choice, but the decision is so wrenching that it has left relatives across three generations arguing about the ethics of identity.