Suicide is a difficult topic to philosophizate.
But this is one of my takes, after a very coldly intellectual fashion. If someone is determined to commit suicide, isn't it better to do it in a controlled situation, rather than involving people who find the body, first responders, etc. etc, all of whom will be traumatized in some way, and all of which will cost money (body removal and care, clean up, inquests, etc.)?
Think about the people who attempt suicide and fail, who get resussed and rescued and finally get the help they need, and go on to live productive and happy lives managing their mental illness or trauma (or both) and are glad to be alive.
Believe me, it's really easy if you've endured a serious trauma to want to end your life. PTSD is like living in a perpetual state of fight/flight peppered by deep depression and when you are in that place you really have no hope that you'll ever recover. You know other people do, but you dont see yourself ever recovering. You cant even imagine it. That's part of the trauma.
Otherwise I would agree with you. If someone is determined to kill themselves, they are gonna do it regardless. Or at least attempt it. But if we had a controlled environment for this and it was legal and accessible to anyone(because I stand by allowing terminal patients to die with dignity how they wish) think about all the attempts that would end up successful. All the people who would be dead, never getting the help that could have turned their lives around.
Instead of failed attempts, they would just go pay to have it done right and they'd be gone. People who would have never wanted to die if not for an untreated mental illness and/or trauma. And even with evals....people suffering severe depression/anxiety/PTSD know exactly how to play the professionals. It's done all the time to avoid involuntary hospitalization. Playing the game, telling them what you know they want to hear so you can get the result you want from them.
The fact that suicide isnt legal or made easy is often the only deterrent for many people going through something that overwhelms them. If it were as easy as going to a tanning booth....that would change. And it could make many people who wouldnt have been determined to kill themselves now determined to kill themselves. When people say things like "well I couldnt kill myself because that would be messy and traumatize my family" or "I just couldnt bring myself to do it, good thing I didnt have a person to do it for me" they really mean that. It sounds like humor and it is....but they are also serious.
Having people able to make this life/death decision for themselves while they are under the influence of a serious mental illness/trauma would have very very tragic results. The blockers that exist for suicide are the reasons thousands of people are probably still with us. That and being found in time. If they were able to just go get it done....they'd be gone.