They may or may not be. That’s not why we banned them.

> simply not true and shows either a lack of understanding of history

Here’s an accessible summary: https://acoup.blog/2020/03/20/collections-why-dont-we-use-ch...

The contemporaneous sources are vast and point in one direction: these weapons aren’t useful for the winners of wars, are annoying to deal with, have a bit of a notion of novel horror to them, and so were bannable. Nobody was talking about extinction.

> their deployment in WWI wasn't asymmetrical, both sides used the weapons

Not what asymmetric warfare means.

> drones are far, far more useful for asymmetric warfare

Sure. But they’re also useful for large military states. So not going to be banned.

Like, someone is free to cosplay a ban. But the incentives to circumvent it are too great. There are no incentives to make illegal chemical or biological weapons because they’re just not that great as weapons.

(I’ll note that your reading of history, while wrong, is far from unique. It’s unfortunately counterproductive as it implies a moral crusade against a category of weapon can get it banned. It might be able to. But chemicals and biological arms aren’t a precedent for it.)