Huh? I guess that depends on your definition of western I guess, since Japan certainly had no issues genociding, testing chemical and biological weapons, and all that other stuff on a wide swath of Eastern Asia? Russia isn’t generally considered by anyone I’ve run across as a ‘Western’ country either, and they had (still may have) a massive program.
Near as I can tell, every industrialized power has gone through the phase.
The comment about nukes is weird, since I believe the US is the only power to ever nuke someone in anger - and near as I can tell, plausibly used it as little as possible and in self defense (though we could talk ourselves blue in the face on that point).
Nothing would have stopped the US from carpet nuking Japan for instance at the time, except some minor logistical hiccups.
My comment about Iran and NK is specifically because they’re consistently isolated by (and start fights/ideologically align themselves opposite) the bulk of countries.
They’ve been, and continue to encourage being ‘others’. I pointed out, they still have no incentive to wipe any groups out/start targeted plagues, wouldn’t start something like this, so why would anyone else?