Does Trump make all Americans Republicans? No.
Did Hitler make all Germans Nazis? No.
(No connection there, just two examples that came to mind, I hate all politics.)
So why does Adam's sin make all humans sinners, at least as far as I understand mainstream Christian theology?
What kind of logic is that? Imputed guilt is what this is called, IIRC.
People say, well it works the same way as Christ representing you. No, it doesn't. With Christ, he is your representative through personal association: faith. Whereas I couldn't care about Adam. It makes no sense.
Think of it like this:
Adam was told NOT to eat the apple. He could eat of ANYTHING in the garden but one thing. Eve was deceived into disobedience, but it wasnt until Adam ate of it that sin took hold.
You may say "But that was Adam, not me." Yet how many commands of Gods do you keep? If you break just one, it is the same as Adam. We ALL have that nature in us.
You may say "Well now God has so many commands. Adam had only one." But did Jesus not say "Love the Lord your God with all your heart body soul and mind and to love your neighbor as yoursel"?
Sure not eating of the tree sounds easy... much the same as love God and your neighbor..... but how many "neighbors" have you failed to love?
We did not set foot in the garden to eat of the tree as Adam, but as descendants of Adam we can not help but choose as he did... no matter how much our hearts and minds are devoted to God, our flesh will always cause disobedience. Not every moment of every day, but we will stumble into sin at times because of our flesh.
Flesh inherited by Adam and tainted by the original sin.
So let's say for example you look at a woman/man with desire that us not your wife/husband. In the world we as humans love to justify it (I can look just not touch... but Jesus said even to look is to commit adultery) just as Adam did after he ate of the tree. He even went as far as to blame God, but he tried to justify his sin by saying "The woman did it, and you gave me the woman so it's your fault... not mine."
Let's say you desire money (We can justify that as "everyone needs it") did Jesus run around worrying about the money? Did Jesus walk around saying "gimme money gimme I'm doing Gods work"
Or did He trust in the Fathers ability to provide?
We can say "I'd never eat of the tree" but the fact that you can not be free from sin on your own is proof that, yes in deed you, as would we all have been deceived by the serpent. Because one simple disobedience is the same as the original act of disobedience.