Declassified documents and vetted leaks/ information like the Panama papers. You can also track the stock lawmakers are trading.

There's good money in "based on a true story". Conspiracy theories sell books, get eyeballs on web ads, make fame, and boost political campaigns. When a person is rewarded for turning their speculations or outright lies into "nonfiction" form, they're likely to persist in doing it.

All human thoughts are collected into a sorta zeitgeist that we all unknowingly tap into. Take for example- when you have a truely original idea, that is then uploaded to the collective human zeitgeist, which thus allows other humans to be able to tap into and have the exact same idea. Some people know how to dive deep and collect this information, and spread it out into the public sphere of knowledge.

Theres classified data leaks all the time. Hell, warthunder has had like 7 leaks now? Its not a small number.

Plus, its not like MKUltra didnt happen.

YouTube, Facebook, forums and pretty much any echo chamber. Pretty much anything that has replaced AM radio and shitty newsletters. In the ~2020's also parroting politicians -- I'm sure I don't need to go over the last 4 years of examples, so how about the Bowling Green massacre that never happened?

Like you said, it's a theory you can look at available data and draw conclusions. The term "conspiracy theory" is used to make anybody they want look less credible.

We know that the government was aware of something that was going to happen in 9/11 but they say they didn't have enough information. We also know that the government allowed perl harbor to happen so they could have an excuse to join the war. Did the government know what was going to happen on 9/11 and intentionally allowed it to happen? I'm sure I found dig up compelling information. We already know what happened in response to 9/11.

In the example of 9/11, there were MOUNTAINS of video footage, news articles, and documents stored in a large array of community archives that started as community efforts to find Osama Bin Laden and as it dawned on all of us, slowly morphed into trying to put together a solid fully documented and supported narrative of what actually occurred on that day.

Community leaders disappeared under mysterious circumstances and then all of those digital archives disappeared.

People who were in those communities and helped to compile those archives saw it with their own 2 eyes and remember what was discovered.

People who were not in those communities don't believe they ever existed.

Edit: Looking at these comments, its just precious.

Question "If the government is hiding information, how did you guys have this information."

"I am older than you, or was more aware than you, and I saw the information before the government hid it and turned a historical record into a conspiracy theory."

"ANOTHER PERSON CONVENIENTLY SAYING THERE WAS INFORMATION AND NOW THERE ISN'T!!! DON'T LISTEN!!!"

Basically the prompt is "explain to me what makes a conspiracy theory", and the comments are saying "IT'S A CONSPIRACY THEORY!!!" in response to people sharing what makes a conspiracy theory...