To better explain my questions, nowadays 'conspiracy' and 'conspiracy theorist' are used to negatively portray someone as crazy, nutty and a lunatic. When in reality the terms actually apply to a wide range of people, including daily activities. How did these terms become so misrepresented from their real definitions and how have they become a term that is used to attack peoples credibility, when in reality, a conspiracy could be something as simple as a group of kids planning to key their teachers car or steal from a shop.
What are you taking as the "real definitions"? A conspiracy theorist is, by definition, one who theorizes about malicious coniving, whether its kids plotting to steal candy from the store or archaeologists hiding the truth about pyramids from the public. Yes, you could call someone who academically studies the plot to assassinate Lincoln a "conspiracy theorist," but the historical and popular idea of a theory is not the scientific one. Anyone who spends time putting together evidence to try and prove the existence of conspiracies, rather than taking evidence at face value, is going to be considered at least somewhat "crazy, nutty, and lunatic," especially if they do so often enough and with enough effort to be called a conspiracy theorist.
As for the word "conspiracy," the word is already defamatory: UNICEF is not a conspiracy to help hungry children, nor did the Red Cross conspire to help wounded soldiers.