The longstanding taboo I think is actually allowing people to commit suicide. This question rarely enters the debate.
Can you elaborate on this? I think it would be virtually impossible to prevent suicide, not to mention various things perhaps not treated as suicide but which are self-caused deaths (repeatedly engaging in very-very-high-risk activity, for example).
* Cultural shame of surviving family.
* Suicide is a sin in some religions.
* Suicide voids most life insurance policies.