My spelling was wrong, but so is yours. It is Lamarck or Lamarckism.
Maybe no-one claimed he was a Nazi and I don't know about his NSDAP membership but he joined the SS in 1937 as a reservist.
If you look at his Stammkarte it has two postings during the war, a relief position in Dachau for a few weeks and a relief position in Prague for a similiar time - other than that he was an academic in Muenster.
The diary has him going to Prague and then being sent to Auschwitz. That may be so but its not on his SS personnel file. His incriminating portion of his diary is recorded in a notebook sourced in either the Protectorate of Bohemia and Moravia or the Czechoslovakia Socialist Republic.
There is no real understanding about how he ended up in trial in Krakow 1947, since such a brief, insignificant visitor from 1942 is unlikely to have been a the top of anyone's extradition lists. A publication of the Auschwitz museum claims that the British searched his apartment found the diary, read it and were shocked, SHOCKED I say. But it suggests a level of surveillence that it is unlikely the occupation forces had the interest or manpower to perform.
So I don't suggest that his Lamarckism explains why he was released early, rather his Lamarckism explains his testimony and his immediate post-war behaviour. In fact if you read his diary it is clear he had got in trouble with the Gestapo as being ideologically suspect.