<< I think there are cover-ups, but it's impossible to say to what extent. >>
Exactly, for me the issue is people love to make sweeping generalizations based on one event or truth that isn't even related or is only remotely relevant to what they're generalizing. I've had a number of discussions with people who attempt to disparage and discredit...oh...let's say judges, claiming they are corrupt or something like that, and their reasoning or evidence for this is that some other judge in a different state 10 years ago was found to be corrupt. They try to bring completely unrelated things into a discussion to back up their argument.
So yes, while it may be true that Judge X from Minnesota was corrupt and went to jail 10 years ago, what does that have to do with Judge C from Michigan today? Nothing, but trying to tell them that is futile.
The same goes with conspiracy theories, they breed and fester into other conspiracy theories or are used as support for other conspiracy theories when they may have nothing to do with one another.
Its one thing to scrutinize an explanation or position and point out any inconsistencies or fallacies within it, its quite another to go several steps further to 'fill in' those inconsistencies for yourself with your own 'theory' about what 'really' happened, often rooted in a person's personal or political prejudices.