Albiet the dark side has killed more but still...
Death Star I
Crew: 265,675
Gunners: 52,276
Troops: 607,360
Infantry: 30,984
Tech: 42,782
Pilots: 180,216
Death Star II
Crew: 485,560
Gunners: 152,275
Troops: 1,295,950
Infantry: 127,570
Tech: 75,860
Pilots: 334,432
Starkiller Base
(Classified) but I would double or triple that of DS2
Starkiller base doesn't even make sense. It's a parody.
shareThink that was DJ's point with the arms dealers selling to both the first order and the resistance.
To the arms dealers they were both bad guys who made them cash and why the only real choice he has no real qualms about only looking out for number one (neither side is really the good guy in his eyes and he isn't going to die for either if he can help it).
Plus if you think death comparable to size of organisation the resistance/rebels must have a higher fighter to death cause ratio than the Empire/First order.