I'm pro-choice, but honestly, I do think they should exist. There are people that it can benefit in a moment of weakness, where they may want to kill themselves, they may even try to kill themselves, but can recover and find happiness. I say that because I've been there, and my suicidality runs even deeper than "moments of weakness".
If it weren't for being 302'd (several times), I would have never met my wife. I would have never experienced happiness for the first time since early childhood. I would have never went back to school, or had dreams of getting my PhD/starting a family, or finding true love.
Things went south... She left, and that's why I'm here... But that doesn't mean that will always happen. Some people may live a full fulfilling life after intervention. IMO suicide should be a last resort, not plan A, or even plan B. You've tried everything, and nothing has helped. If you aren't suicidal after being inpatient, that means you weren't in that "last resort" position. If you are still suicidal, you have every right to die.
Which brings me to my final point: There should be a limit to how long you can be forced into a psychiatric facility, maybe a month? Two weeks? Then whatever your decision should be, it should be left up to you to decide. No would should be forced to live indefinitely.