In the UK, two brothers, aged 10 and 11 at the time, beat two other boys almost to death, apparently unprovoked:
During police interview, the court heard the older brother said he attacked the boys because he had been bored and "there were nowt to do".

[...]

A BBC investigation has already revealed the two attackers were well-known troublemakers and that social services were heavily involved in their lives.
Compassion is a genetic trait.

Some people have more of it, some have less of it, and some people don't have it.

We aren't all the same.

Most people who lack traits that we take for granted don't make themselves visible like this. They live among us and have relatively normal lives, except for little or no compassion, and they show this in small ways rather than large.

I say this because some people have a fiction that there is such a thing as a "brotherhood of humankind", united in values that "virtually all" respect (or should respect) by default.

This is not true. Not only do we not appreciate the same ideals, we don't even share the ability to. Perhaps up to half the human population is evil. We are not united in our sensibilities and ideals. We come together as individuals who agree on a common set of laws to solve our various private concerns.

Societies that understand this, and build on the basis of everyone's self-interest, prosper. Societies that try to build on some non-existent, pre-supposed common idealism, fail.