I concede the benefit of barriers to prevent accidents, or to discourage people from jumping from this point right here. Delaying the impulse. We don’t deny people the knowledge of gravity, and we don’t legistate the removal of high places. If someone really wants to jump they have options, hiking to a cliff etc.

Let’s say there is a magic pill, that is painless, no side effects, etc. let’s say we made this available for people’s pets in pain, but not for humans in pain. In this fictional universe the gatekeeping of “enough pain” to justify a dignified and self selected exit is a net evil. As long as a human has agency they should have a choice without officials gatekeeping their knowledge. (I.e. we shouldn’t nanny adults)

I don’t think the main point of the barriers is preventing suicide specifically, but safety in general. Preventing suicide is more of a bonus.