Yes - USPS should behave like a layer 3 network: moving mail pieces to destination addresses independent of source & destination.

Where elections probably matter to postal services is that they represent a particular shape of mail volume and network usage that may require management to reorganize pickup/delivery resources to meet delivery commitments.

You're missing the bigger picture.

New Mail Voting Rules Moved Forward Despite USPS Officials’ Concerns About Mass Disenfranchisement (https://www.propublica.org/article/mail-voting-usps-official...)

  In a March executive order, President Donald Trump directed the Postal Service
  to create the new rules, including requiring states to give USPS a list of all
  voters eligible to receive a ballot in the mail and requiring USPS to use those
  lists to determine which ballots get sent to voters.
  
  USPS officials were tasked with crafting the details of how the new system
  would work, including the creation of a new portal for states to upload their
  voters’ information and the back-end software that would allow mail delivery
  sites and local post offices to track, and potentially block, ballots
  entering into the mail on their way to voters.