Fox News and One America refused to air these videos because they couldn't track down any of these supposed whistleblowers and in fact, Fox News said they couldn't find any proof that these supposed postal workers even exist.
Also, you do know that the USPS Postmaster is a huge Trump Supporter so any allegations of backdating involving the Postmaster would relate to backdating Republican ballots, not Democratic ballots? And in such case, Project Veritas has provided evidence of voter fraud by the current sitting president of the USPS.
Next time, you may want to think before you link.