They do not need to throttle
It is USA - mostly private peerings. So all they need to do is not increase the capacity of the peering which is p*** them off so it stays at 100%
Verizon has laid out its own set of net neutrality rules it will impose – regardless of whether the FCC keeps its grip on America's broadband service. General counsel and executive VP for public policy, Craig Silliman, said Verizon would adhere to a set of rules on its networks, including policies against throttling, paid …
Verizon conveniently fails to note that it is an ISP and not a transit service (although it may do some of that).
So the Netflix traffic it receives is destined for its own end users, who have paid for the delivery all the way through Verizon's network. The fluff about asymmetry is just that - fluff.