There's one common theme throughout all of these examples of dissonance, that is extremely worth noting here: all the rationalizations require leaps of faith. They require assuming that something must be the case, and really stretching to make something make sense, with zero non-circumstantial evidence that such is the case.
From believers saying, "Well, obviously we did such a good job spreading the faith that Doomsday has been averted!" to doctors saying, "Well, if I can't explain it, it must've just been misdiagnosed," all these are assumptions. Largely baseless ones, at that.
Basically, these individuals minds are closed off, and instead of saying, "Hmm, I don't understand this. Let me do some research and find some evidence for WHY this has happened," they just say, "Well, here's what must have happened!"
Just one more of the dangers of speculation: making yourself increasingly more and more uninformed, and more and more unmoored from the reality of things.
Chase