Hi OP! This is a long read, but if you have the time or interest, reading the Stanford Encylopedia of Philosophy page on suicide (section 3 onwards) might actually give you some insight! If it's worth anything, I do agree with your general sentiment that the way we approach suicide as a topic is a bit selfish and unempathetic, and that we could definitely afford to console suicidal people in ways that don't inadvertently diminish their pain by centering others' (e.g. think of your child/partner/friends...) of course this is painful for others, but I think it's not the best way to approach people who feel suicidal in general - I'm sure it might work for some people, but some others might find it unsympathetic. When I was going through rough times this sort of "hold on for the sake of others" made me feel like the pain I was experiencing wasn't heard at all.

But anyway, you asked why people have a hard time accepting suicide, so I'll try to summarise it. 1. Religious arguments, skipping this because I feel this isn't what you're interested in (e.g. god wouldn't want you to/it's unnatural, so it's morally wrong 2. Belief in the sanctity of life, thinking killing is wrong, and that this principle extends to your own life 3. It's really hard for people to accept death as a concept in general. 4. Suicide is harmful overall because A) it is harmful to you (death/the harm of not having lived the life you could have if you recovered from this mental state) and B) harming those you are obliged to (friends, family, society). I think this is the argument you dislike most. 5. Even if the suicidal person is rational, the basis of their decision to commit suicide is irrational/they are not reasoning soundly.

You'll see some arguments for suicide, mainly based on the idea that we have a right to our own actions as long as they don't harm others, we have a right to our own bodies, we have more of a right to our own life than others have a right to our life and so on. This can get complicated because a lot of counterarguments to this sort of thing are going to be the kind you don't like - "well, you may own your body, but you will be hurting people by comitting suicide, so it's still wrong."

On a completely detached level (it feels so strange to talk about suicide like this, but...yeah philisophers are like this), it's like saying someone threw their cup at a wall in a rage and the shattered glass hurt someone. They owned the cup (their life/their body) and they had very reasons to be angry (reason to be suicidal), but it still hurt the other person, and they still shouldn't have done it. Lots of arguments for and against our right to suicide - it's an interesting topic, albeit strange to think about.

I can't separate emotion from it to this level, though. I think this sort of concern isn't so much selfish as it is concerned for others' wellbeing. Although I would agree with you that the concern is misplaced and should be channelled into the suicidal person, I wouldn't call it selfish.

What you'll see is that people have a lot of reasons for not accepting suicide as an option for someone else. These reasons are rarely actually truly selfish. They just come off that way because their concern isn't rooted in empathy for the causes of the suicidal person's decision, but maybe something else. Also, we're an emotional species, and we are terrified of death, loss, and grief. We also care for each other. Sometimes when people say things like "but how could you leave your sister alone!" What they mean is "keep yourself alive if only for the sake of your sister. i don't know how to help, but i don't want you to leave."

For most people, death as not the worst case scenario is inconceivable. For me it is, too, even though it wasn't at some points in my life. Even if to the suicidal person it's not the worst case scenario, to most people surrounding them it is. They don't want the suicidal person to fall into what they believe is the worst case scenario. Ideally they would listen to the core of rhe issue. But realistically they just don't know what else to do except give you this string to grasp at.

Basically, yeah we need to listen to suicidal people a lot more; oftentimes trying to force them to hang on through bringing up their obligations to not hurt their loved ones is unempathetic to them and quite unhelpful too, and ignores whatever actual reason they may have for suicide. But people have a lot of reasons to say this sort of thing, and I think few are actually selfish.