@Fox_Sama True, but generally we follow (agreed upon) archetypes.
Dwarves, for example, are generally sturdy and stubborn. And generally good. Not to say they CAN'T be criminals, but...rarish.
Demons are generally bad. Sure, you can make a universe where they're not, but generally they're either bloodthirsty, or violent, or both. And tend to be evil.
And humans, well... We are generally portrayed as the wild card. We're not as resilient as dwarves, nor as good at magic as elves. We're something of a middle ground, we hold the "potential" to go any way, if to a lesser degree.
Same with our alignment. We have just as much capability of being good as we do of being evil.