A conspiracy theory is the notion, idea or theory that two or more people agreed, expressly or tacitly, to work together to accomplish something. That "something" may or may not be a crime or a "cover up." Not all conspiracies** are criminal conspiracies.

Labeling something--anything--a "conspiracy theory" has become an instant method of discrediting. However, assuming that everything is exactly as our ruling plutocrats and their minions describe it is both counter-productive and incredibly naive.*** So is the assumption that nothing exists except for those things about which our ruling plutocrats and their minions have previously informed us. (The term "plutocrats" includes, of course, professional politicians, media moguls and probably also wannabe plutocrats.)

No matter how cynical you become, it's never enough to keep up.
Lily Tomlin

With due deference to icon, Lily Tomlin, almost anything can be taken to a ridiculous extreme, including cynicism and doubt. When people find it necessary to prove they exist, cynicism and doubt just may have gone too far: The Age of Reason did not supplant medieval philosophy until René Descartes wrote something that distilled roughly to, "I doubt, therefore I think; I think, therefore I am," aka dubito, ergo cogito, ergo sum, often shortened to "cogito, ergo sum, or, Descartes's own je pense, donc je suis.****