The death sentence in 1st world countries is executed in a somewhat humane way, lethal injection.
But when you look at 3rd world countries, the death sentence is administered in all manner of brutal and disgusting ways.
Firstly, there are no courts in some countries.
People are executed for their crime right there in the street by a mob of angry people who simply decide to take this persons life because he lifted an apple from a stall.
They punch, kick light on fire and in some lucky but rare cases, shoot the person to kill them.
Sharia law in Middle Eastern countries still imposes the death sentence by stoning for adultery.
Adultery, a crime in which a serious penalty would be a fine in a 1st world country, has a person, usually the woman first so the partner outside of marriage has to watch, put in a hole with watered down sides so she cannot climb out. They then gather a crowd of hundreds of people to take turns throwing small stones into the hole at the helpless woman.
These throws cut the skin and break the bones of the woman, then they bring in the larger stones which pin the woman down so she cannot move, while another boulder is rolled into the hole crushing her completely.
If any of the woman is left exposed, it is shot.
The man is then beaten and stoned to death in the same way.

For adultery. Loving someone.

People are executed in front of crowds of thousands of people by hanging. Some are laid down on their faces while a man stands above them with a machine gun pointed at their back, when the crowd cheers loud enough the entire clip is emptied into the man, his body then paraded around the streets.
Men are beheaded with dull knives for opposing a political view.
African women are thrown into long ditches and set on fire simply because they refuse to have their genitals mutilated in accordance with whatever extremist Religion is being imposed upon them.

Street justice is a barbaric and idiotic practice that needs to be addressed.
People sentenced to death by firing squad for minor offences.
Lynching still occurs in parts of the world.
Women tied to trees and ravaged because of something their brother or father did in punishment to them.
Could you imagine if your father or brother was beaten to death in front of you for trying to take a piece of bread to feed your family?
This type of thing occurs daily in countries.

We are not advanced. We are not a civil planet. We are evil at our core.
The world is brutal and most of us should be incredibly thankful we were born where we were so we are not exposed to this type of thing daily.