Dropping from 32 to 8 GW usually means that an interconnected grid has fragmented into islands. If an island has a blackout, you need to black start it and resynchronise it with other islands.
But what prevents you from connecting the stopped power plants to one of those islands and then running it from there? I'm not claiming that is easy, but its not a black start.
It looks to me like the author of this article has fundamentally misunderstood what a black start is. The fact that some power generation remained both on the peninsula, but also on imported power being available means that to my understanding this cannot be classified as a "black start".
A lot of overtime, a lot of careful coordination yes, a black start, no
A black start is a process, not a situation. The situation they're in might not fully necessitate a black start, but a black start procedure might still be the best course of action. Some plants have that capability and the rest (should) have a direct tie to one that does. For all practical purposes, that's a black start.