It's for the starship test flights. Given the nature of the program, the areas are currently "large":
My reading is that SpaceX was loose with their windows because it’s easier and they didn’t think it mattered in a remote part of the ocean. Now that there’s an actual reason, they’ll probably tighten it up.
Nobody is flying or sailing at Point Nemo. The keepout zone typically has a massive 1000km diameter, but approximately 0 impact on anybody.
It looks like this flight is maybe a bit south of Nemo, but in the relative vicinity.
"Santiago Chile to Sydney AUS, 2-3x a week" [0]