You're taking analogies literally.
If you commit certain actions, the entire remainder of your existence will become a living hell. Its irrelevant if that existence stops at death or not.
There are painful things in this lifetime worse than death. One of them is living the remainder of a lifetime unable to shake guilt, worry, self-loathing, and all the other consequences that come with certain mistakes.
One aspect younger folks often overlook is - how they feel about something today is likely not how they will always feel about it later.