I once heard in a lecture that Hitler himself was a victim of gas in WWI, was blind for several days, and came away with such a horror of it that, for fear of it being used by the Allies, he gave orders that it not be used by Germany. The ubiquitous gas mask canister of the German uniform was the result of the assumption that the allies would eventually use gas.
I think you have it exactly right. Hitler was gassed in WWI and is a very risky weapon anyway. The wind shifts all the time. Plus then the enemy will make you miserable too.
Best for everyone to just not use it.