As Hillhurst has given you the information, I suspect that Hugo, for whatever reason, was persecuted in some way and ended up on this list.
If you know your history you will be aware that the Nazis had a program whereby if you weren't what was regarded as pure Aryan, you were persecuted and a great many Jews in particular ended up in concentration camps.
What was done to these people was absolutely appalling and it is probably still occurring somewhere in the world today. There are people/countries in the world today for whom control of the masses is all important and they will use any means to do so.