It makes absolutely zero logical sense to view Islam and Mormonism as "con artistry", only to regard the other Abrahamic cults religions as being somewhat credible.
I can
sort of see the argument for Mormonism at least (although I am not well educated on mormonism or its origins at all).
However I am personally someone who would criticise Islam's "origin story" quite a bit; but despite the many critiques I would do, "con artist" would definitely not be among them (again not super educated on islam so disclaimers apply)