“Conspiracy theory” has meant for a very long time now things which are observable and obvious but are false because the US government has not admitted to their truth yet because these uncomfortable observable realities are detrimental to the interests of capital, and a bunch of obviously insane things thrown in to discredit that which is common sense. It’s literally old school “thing bad so call bad thing bad name then people associate thing bad with bad name” or for the newer generation, anyone who disagrees with the narrative is a Russian agent.