Why is suicide commonly considered a unlawful act/sin?
So many aspects to this question, many of them covered.
The two most serious seem to be:
From the societal control perspective, the last things control freaks want are people exercising real freedom.
From a personal perspective, life seems to be something of a rollercoaster, and while I have been through some rough times, and seriously considered suicide about 40 years ago, I have had so many great times since. So many medical experts have been proven wrong about me.
No one knows the future with absolute certainty.
This journey of life I am on is an amazing one. I don’t know how, when, if, it is going to end, and I am a stand for it continuing indefinitely, and getting better and better as it does so. Such does logically seem to be possible, infinity seems to be big enough to allow that to happen 😉