I think that boils down to the "one is a victim, one million is a statistic" thing- apocalyptic threats aren't as interesting as personal ones are.It bothers me as well, but more as a means to hate the villains of the arc, which is the mark of good villain writing. Hunter x Hunter is pretty good at truly making you wish the antagonists got the most painful deaths ever, which I think the recent special chapters actually did better than anything in the chimera ant arc. It's something Togashi is good at.