Ok I read the first link and their arguing is not very good. St. Paul says in Romans 7:19 “For what I do is not the good I want to do; no, the evil I do not want to do-- this I keep on doing.” Ps. 51 says “I was a sinner from the womb.” Genesis very much evidences St. Augustine’s understanding of Original Sin, yes Adam and Eve brought death upon every one but they also received knoweldge of good and evil, this knowledge is Orignal Sin. If they don’t think it is fair for others to punished for what others did then why do they think it is fair that people die because of Adam and Eve.
In reality the Catholic Church does not teach that people inherit personal guilt for what Adam and eve did but that they inherit the stain of Original Sin and the effects one being the tendency to sin. This is fair because when Adam and Eve were in the Garden they were in a perfect state of grace and union with G-d, so when Adam sinned he did what humanity would have done. Adam spoke for humanity and its desire, if a person in a state of perfect union would choose knowledge (sin) over obedience to G-d then that is what humanity would choose. So Adam spoke for the human race (I hope that is a non-heretical way of defending it). If one doesn’t hold to the doctrine of Original Sin then they will believe that a person can save themselves by being good enough (potentially), but this cannot happen because everyone sins. This doesn’t negate free will but recognizes the neccessary grace that is needed in order to attain salvation. The Church does not recognize St. Augustine’s belief that unbaptized infants would not attain salvation.
