"It is possible to have network infrastructure that has more bandwidth than the consumers can use. Every Ethernet switch worth the box it came in manages it just fine."
Since we talking about networks by analogy, how about this as a arts-graduate friendly analogy: take the road network for the UK. It definitely had traffic management. How about we make that network neutral, by removing all rules for right of way, so that all road users are treated equally all the time. You want that lane and there's somebody already there? Not fair! Just move over anyway.
OK, so we've decided that *some* traffic management is essential. The ethernet switch that you mention engages in traffic management. The question is, does more traffic management make things better or worse?
The thing is, this is not about neutrality or management or anything. What this is about is people worried that ISPs will charge differential pricing to access certain parts of the net, or deliberately degrade access to those websites that don't cough up. A solution to this is to demand that all networks treat all packets equally, a legal solution to a technical problem that would make network switches illegal, since they clearly engage in packet management, holding on to one packet until it has cleared the last, etc.
I don't know what the legal or technical solution to this is, but it helps to know why people are bothered about net neutrality.