I think it's a person's right to choose
There are many religions, and I'm not on earth to judge other people. I don't know if the Christian Bible makes suicide a sin. The Hebrew Old Testament part of the Chrisitan Bible records that God gave Moses the 10 Commandments. One is "Thou Shalt Not Kill". It is contradictory, because God aided his people in wars. Ignoring that, suicide is 'killing oneself', so for Hebrew/Christian's it is unacceptable.
Think it is the Buddha religion that teaches our souls choose to incarnate on this planet to have a certain life experience. Perhaps the soul choose suicide? Or being of that belief, one never would, because one would be too busy learning the lesson.
What if a person holds no belief in a God/Goddess or Higher power? Then suicide is a way to end their suffering on earth. Happy, cared for people don't commit suicide. An unloved person without a home or anyone to love or be loved by, and unable to ever be able to return to the normal world due to society's way of keeping a person down, might find suicide the only answer.
Then their are the very elderly who will never recover from an illness. Did you ever watch someone die slowly, their body rotting away, while they are alive. The suffering and pain! I think that person has a right to suicide.
Not to offend, but if God were as loving as I've been told, he won't allow humans such suffering, that they'd choose to not want to live.