One of the top people in retrovirology turned out to be a crank when AIDS was elucidated, and he couldn't see it. Peter Duesberg (duesberg.com). Also, HPV doesn't cause cancer, after all? He has got Kary Mullis, 1993 Nobel/chem for the polymerase chain reaction, on his side, anyway.
Geology used to be full of cranks. Not just anti-tectonicists, but anti-catastrophists who could not abide bolide strikes. There are still many who can't accept a strike 13kya; they have fallen back on demanding a crater, knowing not all bolides leave one.
A really great geology book, BTW, is "Reading the Rocks", by Marcia Bjornerud.
I'm surprised abiogenesis hasn't attracted more crackpots. there's no embarrassing dinosaur bones to deny or antibiotic resistance to explain away. lots of hints left in virions, archaea and ribozymes, but still a tremendous amount of complexity in LUCA to explain. I guess there's panspermia, but that just kicks the can down the road, and asteroids are a viable explanation for at least e.g. sourcing amino acids.
maybe because nothing's established enough yet to be dogma, and the field isn't practically important other than just being neat.
The "I disproved Einstein" equiv. is "Here's my cure for cancer" (yes, all cancer).
Then there are the anti-Evolution folks.
The AIDS denialists.
The anti-vaccine types.