The vast majority of suicide attempts are caused by temporary, immediate stressors that recede with the oassage of time. 70% of people who commit suicide do so within an hour of of making the decision. 90% of people who survive suicide attempts do not try it again.[1] It is an overwhelmingly impulsive act when people, caught up in the emotion of a major crisis, cannot see any path forward.[1]
I'm not sure if this is the legacy of religiosity, but modern attitudes towards suicide are clinically shaped that understand the fleeting nature and temporary sway of many suicide crises. You present a romanticized view of it(a sober, rational decision made over a period of time, perhaps due to a legacy of classic greek philosophers, that is inaccurate and dangerous. I say this as someone who had a friend commit suicide in 8th grade in a typical dad pushes son too hard academically and athleticly, son feels depressed, finds dad's gun and ends life scenario. He couldnt see the options in front of him... running away, seek emancipation, put up with shit for another 4 years before finally telling his family to frak off...
Public suicide should be illegal for the often melodramatic way in which they choose to end their life and the extreme trauma that witnesses suffer. Watching someone as they jump off a bridge/building, splatter on the sidewalk, or blowing their brains out leaves scars no amount of therapy can heal.
[1] New England Journal of Medicine - Guns and Suicide Rates in US => http://www.nejm.org/doi/full/10.1056/NEJMp0805923#t=article
The court ruling in this case cites a precedent involving somebody handing a loaded gun to a person who said in an impulse that she wants to kill herself and then actually did and another case when people were sentenced for playing Russian roulette until somebody "lost". FWIW, I agree with the first case but the second one is stretching it IMO.
Ultimately, you can't really disagree that most of the time, people generally want others to live, whether they like it or not.