No because justice, it could be argued, could have been to completely exclude for ever and everyone from God's presence....are you beginning to see the objections to personal ideas of justice being the benchmark?
You are conflating original sin with personal sin.
original sin is a fourth century concept. I think that my answer to this would best be summed up to one of your earlier claims that God should have made better humans. Funnily enough Christianity starts with humans in perfect communion with God and they spoilt the image. Think female Movie stars and Botox. Ah I hear you object, their spoiling of themselves is due to their human environment...In which case your excuse for them and their agency actually produces a version of original sin.

Christ of course is God's answer to the human predicament.