Distinction without difference.
Whatever the organization of the USPS governing body, upshot is that those with the power to set prices refuse to do so in a manner consistent with cost realities and profit goals. Any business operating in that manner would have those decision makers ejected by stockholders in short order.
“Have nothing behind it”? Come on! Imagine a grocery store which had two separate boards: one controlled operations, the other pricing, and neither had authority over the other. How long would the store last if the pricing board refused to set to _at_least_ break-even levels? It would be bankrupt in short order! Ditto here: the Postmaster General may run operations, and the Postal Rate Commission sets pricing, and so long as the latter refuses to raise prices to what the former can bring expenses down to match, the USPS is on a fast track to bankruptcy. It’s ridiculous, and you’re defending it!
Tell you what, in my experience, most Congress critters really don't care about the topic. That's why they do nothing, but you wouldn't fire the PMG simply because Congress is full of crooks!
I'd suggest you write threatening letters to your congressman, not make ignant arguments on FR.