This is splitting hairs for no real purpose. Additional risk is new risk.
> By the mid 1920s there was already enough chemical agents to kill most of the population of Europe. By the 1970s there were enough in global stockpiles to kill every human on the planet several times over.
Those global stockpiles continue to be controlled by state actors though, not aggrieved civilians.
Once we lost that advantage, by the 1990s we had civilians manufacturing and releasing sarin gas in subways and detonating trucks full of fertilizer.
We really don't want kids escalating from school shootings to synthesis and deployment of mustard gas.