I disagree with your interpretation.

Would it be better if nobody had access to easier ways to produce new and innovative nerve agents? Yes, of course it would be better.

Do I prefer a world where only state actors can build nerve agents, vs a world that includes state actors plus more? Yes, less sources of nerve agents is more good.

You might as well complain how pointless it is to block proliferation of nuclear weapons when malicious state actors already have them.

The world wont be safer by spreading nuclear weapons to more people, and similarly for nerve agents.

Fortunately, this sounds similar to nuclear weapons in another way, designing the weapon is not the hard part that limits them to state actors, its producing them that's hard.

Still, nuclear powers don't tend to publish their weapon plans publicly, for good reason, and the same logic should apply here.

I'm not using the comparison to imply this is as serious as nuclear proliferation btw, just that it's a useful example of knowledge that really should be kept limited.