I believe pretty much all the Conspiracies I have heard, up to a point.
I mean, no one tells you all their dirty laundry or the Entire truth. There is always something people want to hide from the public. It is Independent Journalists and Investigators that look into the stories, think logically about the evidence they find and tell what they believe could have been possible.
Not always are they 100% right, but parts of them very well maybe.
I am also a Believer of Oral History as well. After all, who would you believe the story of someone who went through something, or the story someone who was not there at that time tells you. (Oral History I mean).
Same can be said for Conspiracies, who are you going to believe?
The officials who gain by hiding the truth, or the people who investigated the incidents independently.