The colloquial muddying of language concerning "conspiracy theory" was probably a government psyop in response to the JFK assassination. There, the officially endorsed theory was a lone wolf theory, that one guy did it by himself without any help or encouragement, and virtually all other theories were theories that involved one or more people conspiring in some way. From there, "conspiracy theory" morphed in media to mean any theory running counter to the official theory, even when the official theory was itself a theory about a conspiracy.