Jones, of course, had his character Loras Tyrell killed off in Season 6, so perhaps that’s led to his headspace that everyone else should either be in peace or die off.
Jones was initially a bit flippant about the question when it was posed to them, and only after some prodding revealed his theory.
Of the two, Henwick is the one to have worked on the show most recently, which almost didn’t get to happen due to Iron Fist’s production.
Finn Jones and Jessica Henwick may possibly know something the general public doesn’t due to their time on Game of Thrones, although it’s more likely the Iron Fist actors are as just as in the dark as everyone else.