I wouldn't agree with that definition. You should know that you can't trust Wikipedia since it's been compromised.
Firstly a conspiracy theory is not a fear - and in short the rest is rubbish.
You should go to a more reliable source for definitions.

https://www.merriam-webster.com/dictionary/conspiracy%20theory

Definition of conspiracy theory a theory that explains an event or set of circumstances as the result of a secret plot by usually powerful conspirators.

First Known Use of conspiracy theory

1871, in the meaning defined above