if you were to take their words for granted you would have to rank Hubbard as one of the more able and intelligent minds of the twentieth century.
He seems to be saying that's implausible. I'm not sure why.
In my view Hubbard was an extremely intelligent and able person; unfortunately he was also a highly manipulative and completely amoral opportunistic sociopath.
I guess Marty is thinking that those of us who are opposed to Scientology's abuses necessarily think that Hubbard was a stupid person. That's not the case.
The complexity, the breadth, and the duration of Hubbard’s alleged fraudulent scheme would be a virtual impossibility for any mere mortal to accomplish.
I'm struggling to see why he thinks this.
The scope / complexity / duration of Scientology is smaller than lots of other organisations - e.g. corporations such as IBM, HP, Google, Apple, governments, other religions - and they were all constructed by 'mere mortals'.
If he's saying that the "Hubbard was a con man" argument implies that Hubbard planned every step of the Dianetics/Scientology journey before starting on it, and never put a foot wrong, then that's clearly a straw man argument.
Hubbard made plenty of mistakes, e.g. losing control of Dianetics, and his megalomaniacal vision of Scientology superceding national governments and taking control of the world was obviously and always doomed to failure.
But none of that means that Scientology's abuses don't exist.
So - playing the game of "what's Marty really saying" - I go with this:
"There's no-one but irrational extremists on either side; I'm the only one who's reasonable".