Why don't terrorists use chemical and biological weapons?

They have been used but only to a limited extent. The difficulty is acquiring them and handling them safely. There is also the problem of transportation to the target.

They require much more detailed knowledge than conventional weapons.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.