Many great minds are in some way flawed, the thing that makes them great thinkers able to come up with revolutionary ideas probably makes them more susceptible to crackpottery.

Examples: Linus Pauling, Peter Duesberg, William Herschel, Isaac Newton, Fred Hoyle, Lynn Margulis

Kary Mullis invented PCR, won a Nobel prize for it, then became an HIV/AIDS denier.

Wolfgang Pauli deeply believed in the occult and Isaac Newton in alchemy and biblical interpretations.