It makes an absurdist kind of sense if you consider that chemical and biological weapons have limited usefulness on the battlefield, and are difficult to use as

It makes an absurdist kind of sense if you consider that chemical and biological weapons have limited usefulness on the battlefield, and are difficult to use as weapons of mass destruction. This in contrast with an H-bomb, which will reliably destroy a whole city in an instant. Nukes are the weapons that could actually end the world as we know it, and kill hundreds of millions of humans, if not billions, if they were unleashed. Even VX can't come close to that.