The source of that purported joke is "sources in the State Department" that talked to TruePundit. If you believe TruePundit had sources in Clinton's State Department, you might believe that Seth Rich leaked the DNC emails to WikiLeaks after participating in child sex trafficking in the basement of a basement-less pizza parlor.
Yeah I dunno. TYT[1] (not a Trump mouthpiece) seem to agree her non denial as likely admission that it was said. "[Clinton] probably said it as a [frustrated] joke".
What in that video suggests that TruePundit's sources were real? Cenk not only falls for the story, he makes up another conspiracy theory out of whole cloth by saying that "non-legal methods" in a Clinton email means illegal instead of methods that don't use the courts.