Hitler saw Germany as a nation that was governed by Arians (white people with blue eyes), pure Germans that were the. supreme race in the world and the handicaps (physically disabled) did not fit in his ideology.
Thus, most of them were taken of the streets and send to concentration camp were they were forcefully allowed to work if capable but most of them were executed by gunshots.
This allowed German to be seen as the supreme nation filled with healthy well educated Arians in the background.