What often distinguishes the crackpot from the visionary is whether they are eventually vindicated. The latter usually begins their career being perceived as the former.
That doesn't mean that being perceived as a crackpot is a reliable indicator of being a visionary. It's similar to the argument that opposition equals confirmation -- some religious groups and conspiracy theorists argue that the fact that people oppose them means they are right.
"They laughed at Columbus, they laughed at the Wright brothers. But they also laughed at Bozo the Clown."
Given all the evidence, I consider the MFAP origin hypothesis to be significantly less likely than the primate evolution theory. Extraordinary claims require extraordinary evidence.
He had a lot of weight behind his claims.