Logical Riddle - Aggression And Pain

What is life of other for you?
What is pain of other for you?
What are stranger eyes for you?
What is their scream for you?

What do you need for your happiness?
Who's not yet been put to death,
When will you finally calm down
And stop taking lives away

This cruelty causes aggression in me. These sufferings cause pain in me.
Hearts are stoning, but satisfied stomach's
Hands in blood, but persons with a fat smile.

Weakness to change something causes aggression.
pain streams on through veins in heart.
When will an end come?
I have no power to change a world.
But I can change myself.
And this will be beginning.