This is code that runs in each child when the parent dies. In other words, when the parent dies, the children are so upset about it that they commit suicide. It could very well be that the parent doesn't even know how many children that it has.

Killing the parent causes the children and their kids to "suicide". I hope that you can forgive my thinking that, hey "kill the parent which kills the whole family", and then make a new parent which makes new kids sort of thinking... I guess that is grossly immoral, but it does have a certain simplistic logic to it.

The alternative isn't much better: tell the parent to keep track of all of the family (instead of the OS doing that) and then ask the parent to kill off the "clan". This is an "OS like" supervisory function. That is certainly possible. I see no technical problem with a strategy like that being implemented.

I guess, paraphrasing the ancient saying: there are many ways to Rome.