Tangentially, there should be a streamlined euthanasia option to those serving very long prison sentences.
For what it's worth, you're not the only one who believes that. My world-view is also heavily rooted in the notion of "self ownership," and I hold that an individual has a right to end their life whenever they want.
That's not to say that suicide is (often|ever|usually|whatever) a good idea; and I'd be the last to encourage someone to commit suicide. But it is a right, and I believe it can even be a totally rational choice in some cases.
If you have the right to your own life, then do you have any obligation to other people's lives? Also, how do you know you own yourself: did you create yourself or did your parents? And who created them? Would you ask your creator if it's okay to suicide, and then would you be open to answers?
Lastly, are you sure you die when you die: how do you know the pain won't go on someplace else?
From my reading, suicide thought is a transient state but with permanent consequences if acted upon.
Also, the best way to fix your mind, is to fix your body, rather than destroy it.
Maybe this Diaspora fellow thought people wanted to kill him, so he thought he'd do it himself to save them the trouble because he'd already let them down once. Who knows.. but that's an ill thought process to have.