The mail analogy is that some items have special requirements for handling and routing. I won't route Hazmat through post offices that can't handle it just as I won't route high security network traffic through China. Shipping perishable goods requires that those goes be given prioritization so that the arrive before spoiling. Real time voice data requires a minimum time delay. Is it OK to prioritize voice packets over other data to ensure quality?

Another question you might ask. Is it OK to prioritize data that is destined for the 911 network over data that is heading to Pornhub? What about a university? What about Khan Academy? What do you do with encrypted data where you can't tell the type or destination? What if the encrypted data is malformed such that it is causing detrimental performance to the broader network?

Management of a modern network like the internet is an amazing challenge that requires all kinds of work to find optimal solutions. We need real technically nuanced discussion and consideration to craft legislation that actually solves problems and doesn't create significant new ones. We don't need badly flawed analogies designed to garner public support that only apply if you don't know about the topic.