If my ISP is hitting peak throughput at 8pm on monday night, it makes sense for high priority traffic to pay for priority (streaming, telephony, etc), while low priority traffic (bittorrnet, dropbox updates, etc) slow down because they are unwilling to pay.
I don't think outright blocking is justified or even purposeful slowing down (rather than speeding other stuff up). But i don't think treating everything the same is economically justified.
Your argument is usually what I tell people when they ask about NN. It's a lot more complicated than treating every packet equal because at capacity networks want to manage bandwidth.
You could also think of it this way, why should the general user be required to subsidize a heavy BitTorrent user's traffic? Now maybe ISPs shouldn't oversell in the first place, but the operating state of a network is congestion.
Your argument is very moderate and is not NN, but it's close. I would tend to agree and prefer what you describe: content neutral bandwidth management. But that's pretty much an oxymoron.
This has the effect of enforcing net neutrality, which is why everyone is in favour of it. However it also gives the FCC the power to censor content, like they did with television and radio in the past.
Net neutrality is simply tha concept of treating access to the network (in this example the ISP and the greater internet it connects to) where it does not prioritize one set of bits and simultaneously and purposefully (and typically for the exchange of money) slow down access to something else.
Bandwidth management, or the idea of prioritizing on the fly to ensure quality service, does not inheritantly violate those principals. What does is if the video people paid th ISP money for faster bits and to slow down competitors and/or the ISP slowing down competitors to promote its own services.
Notice it also has no legal framework for specific types of access or information, simply that the pipe should be neutral and non-interfered. In fact, net neutrality laws can help improve privacy and gives more standing for companies to fight back against gov surveillance