Arguably their careers are now both collectively and irreversibly ruined. Like the Nobel prize winner that invented some major form of fertilizer that turned out to be a nazi

Assuming you are talking about Haber, you couldn't be more wrong. He was actually a German Jew (convert to Lutheranism) who was forced out of his position when then Nazis came to power than died en route to Mandatory Palestine in 1934.

He discovered the Haber process around 1911, which was well before WWII and it was intended for fertilizer only. Eventually people realized that mass ammonia production was very helpful for chemical warfare, and many (including French nobel winners like Grignard) engaged in it.

The Zyklon B synthesis is a red herring.

Mandatory Palestine is a new term that has been invented post world war 2. Back then, it was simply a country called Palestine, as can be seen from passports issued in that era.

Like the Weimarer Republik (in reality still called Deutsches Reich in the republic's constitution). Nevertheless, it is useful to disguish historical periods of the country.

Fritz Haber was not a Nazi. In fact, he was Jewish, and was forced to leave Germany when the Nazis came to power. His involvement with chemical weapons was during WW1; he died in 1934.

In addition his involvement with chemical weapons took a huge toll on his wife Clara to whom he wasn’t the nicest to begin with