It's an attempt to invalidate all conspiratorial suspicions from the get go. To shut down conversation about a conspiracy as if it is somehow nutty or paranoid. Not surprising since the majority always controls the language. Noone actually WANTS to believe there are conspiracies. Best to dismiss their very possibility without even looking into the evidence.
Except typically, once you introduce actual evidence and solid facts, it goes from a "conspiracy theory" to a legitimate theory.