The comment referred to the fact that the Nazis produced soap from the body fat of dead Jews at extermination camps. The person who wrote this must have felt that the Holocaust happened because the Jews did not take their safety seriously enough. That is a truly haunting thought.
verb [T] ━━ vt. 根絶する.
to kill all the animals or people in a particular place or of a particular type:
Once cockroaches get into a building, it's very difficult to exterminate them.
Millions of Jewish people were exterminated in concentration camps in the Second World War.
International measures have been taken to prevent the extermination of the whale (= all of them being killed).