Thanks my dear friend,
You said "Who's responsible ?".
By looking at the history, it is seen that two classes in every society have the most responsibility for killing people in large scale.
One of them is Politicians and the other is Clergymen or Mullahs.
You see the crimes of Hitler, for example, as a politician.
On the other hand, from about AD 1100 to about AD 1400 there was the middle ages in the Europe, which the crimes of clergymen are seen.
Also similar crimes can be seen by the Islamic clergymen or mullahs, such as Khomeini.
In the past and also nowadays, the dictatorial powers kill or prison innocent people in some places of the world.
A man (or woman) is right that Who can be alive or dead … Why ?
Because some people have adverse beliefs, they must be killed.
These criminals have a common characteristic. They want to have more power to govern people.
Now another question may be asked, " What is the solution ?"
I think the solution is in the people mind. If people think and do properly and keep in their mind that everybody has the right to live and enjoy this beautiful world, we can have a nice human world too.