Because bad people have some good sides and good people have some bad sides.
But when you look at the sum total of life, the good ones always win. Especially when you consider the afterlife and the world life together, the real picture emerges.
You know nothing about the afterlife, I know a lot more that you because I have spoken with spirits who have taken mediums in trance. They say there is no hellfire, and no Satan, and there will be no judgement day.
All you have to tell you about the afterlife is the sick verses in the Quran, which is all the lies of the false prophet Muhammad, who made it all up.
Here are some of the horrible verses Muhammad designed to scare people.
22.19 These two antagonists dispute with each other about their Lord: But those who deny (their Lord),- for them will be cut out a garment of Fire: over their heads will be poured out boiling water.
22.20 With it will be scalded what is within their bodies, as well as (their) skins.
22.21 In addition there will be maces of iron (to punish) them.
22.22 Every time they wish to get away therefrom, from anguish, they will be forced back therein, and (it will be said), "Taste ye the Penalty of Burning!"
4.56 Those who reject our Signs, We shall soon cast into the Fire: as often as their skins are roasted through, We shall change them for fresh skins, that they may taste the penalty: for God is Exalted in Power, Wise.