I always laugh at people who oversimplify conspiracies so that it becomes an "us vs them" straw man. It is more complicated than that. A few people want something, device a strategy, and then try to convince others how the goal they're trying to reach would benefit them while whitewashing the idea into something very legitimate.

This is such an everyday approach to handling things that people would never call it a conspiracy, the label is only applied when something is so outrageous that we struggle with coming to terms with it, and then we turn it into a caricature so that we can simply discard the idea.

It is never "the government". But in the 90's, a cabal of neocons drew up a plan to tighten their military grip on the world, and when 9/11 came along, they had an excuse to execute it and start waging wars in a bunch of countries while convincing everyone and the government that we were battling terrorism. That is how a conspiracy works.

To give you another example, over the course of decades, the UK sprayed millions of it's citizens in secret chemical warfare tests that resemble the popular "chemtrail" theory. A testimony to how compartmentalization is perfectly able to keep secrets when needed. And even now that's in the open, very few people know about it.

But in reality, there's often no need to keep conspiracies secret when you were able to convince the majority of people that conspiracies don't exist. All that's required then, is to call something a conspiracy, and people will turn out it droves to mock anyone who dares to suggest its legitimacy.