As the internet is originally mainly created by American culture it is obvious that its different aspects penetrate the global public consciousness produced by the internet.
In that way the word "Conspiracy" in connection with the term "Conspiracy theory" experienced a career in public discussions.
For that reason it is useful to objectify this meanwhile commonly used term by showing its historical and cultural background.
One point to be made is that the same word has different impacts within different cultural contexts as criminal law shows the extent of each society to marginalize determined circumstances from commonly as useful recognized goods.
One marginalized good in Anglo-Saxon jurisdiction is "Conspiracy". Therefore, this word is emotionally loaded because it is being defined as criminal.
You don't have this kind of emotional charge of the word "conspiracy" in the European continental jurisdiction.
Nevertheless, it is being used in the public controversy over different topics to marginalize single persons as weirdos. That way the word "Conspiracy" became a way to marginalize people without criminalizing them.
To the opposite: it has even a stronger effect in the public discussion as the psychiatrization of people makes them even more unacceptable in a public discussion than criminals. A criminal is at least being admitted to have a common sense. But this is not the case with "weirdos".
In the public use of the term "conspiracy theory" a - as a "Conspiracy theorist" qualified - "weirdo" has only theories about an alleged conspiracy. The term "Conspiracy Theory" disqualifies to use juridical methods for qualification of a statement of facts although it is usually societal recognized to use circumstantial facts in court proceedings.
Therefore commonly speaking the sprachregelung of publicly discussed topics has the political function of the kind of consciousness of being allowed in public.
The prevention of developing a consciousness beyond the politically wished imagination of the world is the method to marginalize persons who are asking uncomfortable questions.
The politically wrong consciousness leads to politically "wrong" consequences.
The criminal meaning of the word "Conspiracy" from the Anlo-Saxon jurisdiction is used to marginalize any "Conspiracy theory" from public discourse as the meaning of the word "theory" is psychologically infected by the criminal meaning of its foreword.
If you analyze this context this kind of public consciousness formation is a contradiction in itself as the scientific meaning of the word "theory" is completely absorbed because of its criminalization through its foreword. In addition to it the word "Theory" appears to be squishy like a cloud for common man as it is not empirical yet. There is nothing tangible with a theory although - scientifically used - the development of a theory is the precondition for establishing consolidated science. This and the described contradiction before create the ban on thinking needed to use the term "Conspiracy theory" in the way politcally needed.
Therefore the impossibility to investigate a conspiracy theoretically by using the juridical method of circumstantial facts.
That way you exclude whole topical areas from being negotiated within the political system and publicly.