What you're talking about is actually the cliché of a "conspiracy theory".
A lot of things that are called like that aren't anything one could call "a theory" at all. The point is: Any random BS claim isn't a conspiracy theory.
A conspiracy theory is nothing more than speculating that some parties are working or worked together in secret (conspired) to achieve something. That's all. Such a theory can usually be falsified. (At least in theory).
But there is this framing that "conspiracy theory" means some arbitrary BS. That's actually why labeling something as "conspiracy theory" immediately shouts down critical thought in a lot of folks. Just call something "conspiracy theory" and the cliché kicks in and people will dismiss that something as BS.
By the way: The English version of the Wikipedia disagrees. But only the English version. I've also looked at Boarisch, Deutsch, Español, Français, Italiano, Nederlands, Polski, Русский. Only the English version adds that a conspiracy theory "is an explanation for an event or situation […] when other explanations are more probable. The term has a negative connotation, implying that the appeal to a conspiracy is based on prejudice or insufficient evidence." Should we proceed to construct a conspiracy theory form that observation? Someone got obviously their framing into Wikipedia!