"Conspire" means "breathe together" in Latin. Conspiracy is intimate. The conspirators are vulnerable to each other, open with their thoughts because they have common interests. The conspiracy must remain secret because it only serves those interests.
From this point of view conspiracies, and by extension conspiracy theories, are as natural as communication. Why then does no one today say, "I have a conspiracy theory"? We all have conspiracy theories, but voicing one invites ridicule.
Perhaps the rumors are true, that the CIA promoted a negative connotation for the phrase "conspiracy theory" to embarrass people who doubted the Warren Report on President Kennedy's assassination. If that conspiracy theory is true, it was a brilliant move, stunningly successful.
It's interesting too that the word "paranoia" is understood by almost everyone while its opposite, "pronoia" (referring to denial that there are people conspiring against one, when in fact there are) is mostly unknown.
Of course, even if someone overcomes the stigma of vocalizing a conspiracy theory, and even if everyone who hears the theory agrees with it, you still face the question: What are you going to do about it? You can't take legal action because a conspiracy theory is a theory; it is not designed to be a formal allegation, as there is generally little or no evidence to back it up.
For instance, I have a conspiracy theory that Big Pharma is behind the move away from attributing significance to dreams, which are referred to in many medical journals as neural "trash" to be flushed down the toilet of sleep. My theory is that the downgrade occured because there is no money in dreams, as there is in drugs. If dreams have meaning and are studied, as was the fashion in Freudian times (e.g. Beverly Hills, circa 1960), and if people are able to assuage life's problems by talking about dreams- as believed not only by Freud but by numerous human cultures- that's not good news for a system in which mental health is addressed with prescription drugs, which means it's not good news for stockholders.
The term "depression," too, has been co-opted by Big Pharma. In the past, a state of depression (previously melancholia) indicated that a person was "sad," a term that is avoided in the pharmaceutical world because we understand that sadness can be caused by the world outside the sad person, and there's no Rx for that. Today, the person is affected not by the outside world, but by chemical imbalances within. That's where the money is.
But what can I do with my conspiracy theory about Big Pharma other than blog about it? There's no legal action to be taken since I have no evidence, and because the pills often work, there's little hope of inspiring a pro-dream movement against medical science. People would think: What have dreams done for me lately?
The only struggle for change I'm interested in is the struggle to reattach a neutral connotation to the phrase "conspiracy theory," so that, if you laugh at my theory about Big Pharma nixing dreams, it will have to be because you can prove it isn't true, not because I can't prove it is true.