As far as certain "elite" are concerned depopulation will happen regardless. We are faced with a coming E.L.E and "NCSWIC". Even with all the DUMBS and other underground shelters it's not likely more than 50 million humans will survive the event and the years, maybe a few generations, before the surface is habitable again. Killing off several billion now just reduces the number who will die in terror latter. More to the point it has been determined that the greatest chance of survival for those going underground is if those surface dwellers are eliminated prior to the nova event. Don't need a bunch of useless eaters piss'n in vent shafts and causing trouble.