[IYAS9YAS]

If there is no moral qualms about chemical weapons, why did even Hitler shun their use in WWII?

Because Hitler suffered injuries (temporary blindness) from a gas attack in WWI. Note that he had no compunctions about using them on Jews, and others he considered undesirables, in the death camps. He simply didn't want the fighting forces of his superior race (said with dripping sarcasm) being attacked with them.

http://www.history.com/this-day-in-history/adolf-hitler-wounded-in-british-gas-attack

[elhombrelibre]

Well, he wasn't ammo so he wasn't shit.

Of course, he had no compunction on the Jews.