Why do people dismiss instantly the ideas of conspiracies about anything so carelessly?

No one dismisses the concept. It is just that human beings decide what is an actionable conspiracy. The Kennedy conspiracy does not seem rational to me. Time has rendered that discussion irrelevant because it is just shy of 60 years old. The Lincoln ination case has been cleared to the satisfaction of most. Many of us who live in your nation recognize that your major media outlets can expose most conspiratorial activity. As it it wishes. And as it wishes not.