Earlier quoted context omitted.
Unfortunately, if one allows oneself to believe that too much, it's mental permission to commit suicide. After all, committing suicide is just as much a valid task as anything else, like writing a book or making a chair. It's an extremely hard one, too. But since others have and will go through it, as you say, it becomes that much easier. Especially when you're resolved to face it calmly and equanimously.
That's quite an interpretation. I suppose "memento mori" can be argued in the worst sense as leading to nihilism. However, it'd be impossible to say anything of substance if we were constantly trying to avoid any worst-case interpretations. Most reasonable people can surely understand there's a difference between the colloquial usage of death versus suicide.
I think it’s not possible to understand unless you know the feeling. You’re right that most people don’t. But many do: Robin Williams, David Foster Wallace, Aaron Swartz.
I don’t claim to speak for them, but if any of them used it as an escape — which seems somewhat likely - then they’re examples that the logic can be turned against someone strong, using their strength against them by encouraging them to accept the inevitability with composure.
You’ll have to take my word that there are many more of us than those famous examples, though.