There are sick and cruel people everywhere. What you do not know is that sick and cruel people are indeed everywhere and most people.
It just that we bullshit even our selves that we aren’t.
Humans mainly care about themselves and their family. They also want to max out control of other humans in their greed for power. Also what makes humans happy is relative success rather than absolute success. Hence, humans instinctively want to fuck over any happiness if those happiness belong to others. That’s our true nature.