The morality stands, Sith have none, Jedi bend easy with it sometimes
Most Jedi and Sith are just extremists. Mindless monks vs. crazy butchers. Just because rigidity of jedi and incredibly simple fall to the dark side. Galaxy would appreciate more grey Jedi and Sith with another passions than just pathetic anger.
Also killing lead to the dark side is only problem when you killing with anger. When youre cold self-controlling assassin, you cant risk to be consumed by DS (trick of grey jedis), or you can channel another passions. For food, sex or money, so good or risky life. (trick of Sith, what dont want be lured completely by DS to losing control)