Stangl was talking about the Aktion Reinhard camps that he worked in (Treblinka, Sobibor, and Belzec). Those camps were dismantled in 1943 after having served their purpose, and therefore the personnel had to be deployed elsewhere. In late 1943 that meant the frontline, as things were heating up for Germany.

Stangl may have wished to land a cushy desk job somewhere, but that didn't happen. It was all hands on deck, and he was never a well-connected man.

Compared to the life they led in the camps (SS officer Kurt Frank titled the photo album he kept of his time in Treblinka Schöne Zeiten - "the good days"), being ordered to any place where there was actual fighting would have been a huge shock to these men.

Many were sent to North Italy to fight the partisans, some died there. A few ended up as staff of other camps (Majdanek, Buchenwald, labour camps). However, the majority we have data for survived the war.