Earlier quoted context omitted.
There are other reasons they want to disband the post office beyond just its impact on voting. If they replace it with private entities it becomes easier to surveil and censor the mail, for instance.
There was this incident a while back. Some psychopath sent letters threatening to kidnap young females, rape them, and kill them. He talked about how he had rigged out a van to facilitate this. His letters got turned over to the FBI, since they would up in different states. Turns out that each stamp has microprinting on it that identifies it. Given the stamp, they were able to identify which post office it was sold a…
But yes, the postal service has already been turned to this purpose in many ways and the days of "gentlemen don't read each other's mail" are largely over.