The problem is not that Adam and Eve sinned, but that all have sinned.
You are right in the fact that I do not blame Adam and Eve for my previous condition, in fact I thank them for living through the whole Garden situation to the point of being kicked out, because it helps me (and I am sure them) to realize how lousy the Garden situation was for fulfilling my earthly objective. All mature adults will ask at some point in their lives How could a Loving God allow this to happen? God needed to and did address that question at the beginning (not with blame Adam and Eve, but with the situation without tragedies does not provide the best situation for fulfill your objective).
Sin is not the problem and has purpose.
Yes my friend, all have sinned
because they are born into Adam's race. In other words, you don't become a sinner by sinning, but the reason people sin is because they
are sinners.
David tells us that he was born into sin and conceived in iniquity. He's not a special case.
You don't have to teach a child how to lie, cheat, steal, disobey parents, violently hit his playmates, be selfish, etc. They innately know how to do that. That proves that mankind is sinful by nature. The fact that they don't have to be shown how to do that, but that they know how to do it by nature, proves that they are sinners and
that is why they sin.
Humans are born into a fallen race. Adam was their representative. Adam brought sin, guilt and condemnation upon his entire posterity. Paul is clear in Romans 5 that men die because they are guilty in Adam, not merely because they are guilty for their own sins (though that is true, too). Adam represents his people in the way Christ represents His people. Christ is considered, by the Apostle Paul, a
type of Adam. (and vice versa)
That means what Adam did affected me, but what Christ did affected me to. If you deny original sin that means you deny Paul's argument that Christ is a type of Adam, which means you deny that both parties (Adam and Christ) act as federal heads for the people they represent.
If you deny Adam as your federal head, then to be consistent you must deny Christ as your federal head, too. In short, if you deny original sin you also deny the very doctrine of salvation itself!