So if someone tries to commit suicide, say by hanging or gunshot or slashing their wrists, you say don't try to save them- just let them die?

Human society doesn't act in that way. First, we act to save lives regardless of how the life-threatening situation came about. If someone later goes on to kill themselves out of our sight, there's nothing we can do to save them. But we did our best, and that's how a society evolves for the better. 

Canadian society works on the following principle: if we can save lives, we do. Sometimes our efforts will come to nought, but we do it anyway. If you think you've got a better principle to base Canadian society on, let's hear it.