Come on, nukes are not feasible to goddamn governments. The hard part is not "the science" behind it, the hard part is spinning stuff at such a high rpm that a tiny vibration will have the whole thing catastrophically collapse, that is refinement..

And basically every bad thing has already been available on the internet. We can't really do much about it, you can take out plenty of people with a single car, let alone biological weapons that are much scarier and easier to produce than goddamn nukes (which btw, even if you had one, what you do with it? Explode the neighborhood? Because you ain't transporting it anywhere meaningful, thats for sure. That ain't fitting your on-board bag on planes)