Reading between the lines here, it seems fairly probable that Truecrypt has either
a) Very serious security bugs, or
b) Had backdoors introduced by the NSA.(Does Truecrypt use elliptic curve cryptography?)
In either event the code is basically tainted and shouldn't be used for any future projects.
The vague and sometimes bizzare nature of the statements from the Truecrypt dev team, including this one, lead me to believe that they have been placed under a standard NSA gagging order and have decided to burn Truecrypt rather than see it be turned against its users. Comments like "Forking is Impossibe" appear to be an open code for communicating that they are essentially unable to communicate, but that Truecrypt is no longer a trustworthy piece of software.
Reading though the Lavabit case, it's clear that those placed under NSA gagging orders have very, very little room for legal/media maneuver, but nevertheless still retain the freedom to walk away from their projects and tell others not to use them. Such actions appear to be the last defense of cryptographers in the US, and I think that is what we're seeing with Truecrypt.