It wasn't ordinary knowledge. Adam and Eve were privileged to only know GOOD. And they were told by God NOT TO eat of the Tree of the knowledge of good AND EVIL.
Once they disobeyed God's instructions and ate of that bad Tree, they then knew evil as well as Good and began practicing it because they had an evil nature.
We are born of the same evil nature as Adam because we have his bad disobedient genes inherently in our nature.
That's why we sin and we all need forgiveness.
It was a crime against God because they were commanded NOT TO. Parents teach their children not to do certain things for their own good. God told Adam and Eve not to eat of that tree for their own good.
That's why it was a Crime because God knew what would happen - and it did, when they disobeyed.
The whole world FELL and we from then on are all born with sickness, disease, sin and death in our genes.
Before that happened, nobody was sick, nobody died physically and there was no sin, or physical death or distress. It came in with Adam's disobedience