The only terrorists who wanted to end the world were Aum Shinrikyo as far as I remember. Everyone else is fighting for a cause that benefits their people - some good like kicking out colonial oppression, some evil like fascism or Islamism, some of them in between like various ethnic conflicts.

Even the religious extremists don't really want to take over the world and destroy everyone who doesn't convert. That's just a way to gain support from a conservative nation. A lot of them are motivated by revenge for wars that destroyed their country and want to make sure it never happens again.

Their methods are wrong no doubt, and not very effective, but the reasons they do it are good. And a person like that will never release a deadly bio weapon. We should worry more about incel mass shooter types who believe everyone is evil.