Probably a stupid car question...

[eppie]

Ah, but it only takes one, or perhaps a small group, to do vast amounts of damage.

--Pete

Although I agree with what you wrote it wasn't directed to what I meant.

Nuclear weapons and biological weapons sophisticated enough to 'kill billions' are indeed luckily not easy to make for anyone with an internet connection.

I think potential terrorists would not wait with their attack until a nuke becomes available. They would probably use something more low-tech.
So although I share your concern about 'it only takes 1 or 2 people to create disaster' I think we could better use large part of our anti-terrorist resources for other things (like telling the 90% of people with a drivers license that can't drive safely to stay at home for example).