Yes it is wacky, and the passage you link to is nothing but bloviation. Take the illogic of this statement, "That none of his manuscripts has survived has been taken as evidence that they were destroyed to conceal the identity of their author." If that's evidence, then what are we to make of the lack of manuscripts for Christopher Marlowe, Robert Greene, Thomas Kyd, Thomas Nashe, John Webster, John Ford, ad nauseum?
And the statement is false anyways, since a portion of "Sir Thomas More" written by Shakespeare does survive in manuscript. An extremely rare bit of luck. If I remember correctly, out of thousands of plays written during Shakespeare's time only about 20 have been preserved in manuscript. People who make arguments such as the one you cite really know nothing of the period.