Now I think of it, this phenomenon made its appearance here.
The adoption of every GOP conspiracy theory from Obamagate onwards. And even when shown the list, the lack of realisation about what that showed. Being in on the latest theory seems to have a druglike hold.
Maybe it's a bit like the old Wave community with its pot of gold at the end of the rainbow. The core believers have no doubt, with the latest dollop of hope driving them forwards.