The actual work required to execute such a plan is vastly more difficult than being told how to do it. How the original atomic bombs worked is well-known, but even nation-states struggle with implementing it.
For nukes I agree, and that's the main reason I'm less worried about nukes. But for bio it's mostly a matter of knowledge and not resources: for all the parts that do need resources there are commercial services, in a way there aren't for nukes.
