That wasn't a "conspiracy". It was government policy.
tbf. I read that as Jazzz saying his granda's tendency to belief in conspiracy theories led to him taking pre-emptive action in removiong himself from Germany.
People would do well to remember that lots of the German Left just laughed at the Nazi's - and dismissed others arguing for pre-emptive strikes as conspiraloons (although I'm sure they had a german word for it - they seem to have a word for most things) - right up until they were lifted and sent off to the camps.