because
1) they were only found on the school president's computer but not elsewhere because of
a computer changeover at PSU in 2004...this is somehow supposed to make the emails
less valid. and
2) They weren't written by Joe but on his behalf and they mention that "Coach wants to know
how the investigation is coming" and that the "Coach" being referred to "could have been"
Sandusky and not Paterno even though the high level writer of the email was Paterno's
running boy.
They are saying that this is not enough of the kind of strong evidence needed to convict a person.
All, in all, a big waste of money aimed at creating plausible alternatives to a simpler & more obvious reality that most of the public has come to believe.