Those who are at the end of their rope mentally, emotionally or physically.
Those who are too immature to understand that the down turn is temporary and the sun will shine again.
Those who want other people to suffer even if they have to die to do it.
For the third type your "law" would be a gift.
Besides on what legal or religious grounds would you basis this kind of law?
It was a joke - trying to stop suicide by killing others.
And yes - it would be a blessing to those left behind. Our pastor’s Dad killed himself when the pastor was just a child. He spent a long time wondering if somehow he caused it, and of course growing up without a father.