Net neutrality should be mandatory and non-negotiable.
Net neutrality bans access fees as a kind of blocking and throttling.
Twitch's servers almost certainly directly connected with the three largest ISPs in Korea. And Korea has a regulation that requires them to pay those networks and it looks like the fees that were demanded were way too high. And that's what you get in an economic system where monopolists (ISPs have a terminating monopoly over there) are allowed to set prices.
Transit costs 10x what it costs elsewhere. You can't just neglect a 10x price increase when the cost sending video to users in the bulk of the expense of offering twitch in korea
From what I can see, twitch is a business that benefits from the fact that most internet companies don't actually have to pay for internet connection services relative to their usage.
They're mad that forcing them to pay relative to their usage breaks their business model that relies on being subsidised by other internet usage and users, how does that have anything to do with net neutrality?
If anything wouldn't it be more in line with net neutrality to require that servicss that use more of the internet infrastructure pay for it instead of being subsidised by users of other services/sites?
If the ISP is acting in the interests of its customers, it would make it as cheap as possible for twitch to send the data that its customers want.
If a business you are dealing with makes money some way other than by charging you for the service they provide, you're not their customer, you're their product.