It's very sad that you've been made to feel so isolated throughout your life. Even if such thoughts might be controversial, I think it's understandable why someone would compare and draw parallels between themselves and others who have passed on, hearing stories that strike a chord with us and stay glued in our in our memory with salience often bring about reminders of our own fears, regrets, unfulfilled desires, and so on.
The woman's story likely stuck with you because of this. When a good friend of mine passed, I really wished that I could swap places with her and that she could have another chance at life instead, because she was truly loved and cherished by many people. I can't say the same about myself. No one is going to care enough to even write me a eulogy.
I see motivational quotes and posts all the time about how suicide is never an option, because someone out there loves you. While this probably does help certain populations of suicidal people feel better, it only makes me feel worse because it draws attention to the fact that I am alone. So I understand how you're feeling, that isolation is an awful thing to experience, especially when you've reached out before and the pleas have fallen on deaf ears.
Someone I have known for over four years at this point and who I considered a friend randomly told me that she wouldn't care if I ctb and died tomorrow, out of the blue. When I realized that I was merely a background character in other people's lives, it only made me even more suicidal. I really feel for you, because I know how badly this hurts, to know that people don't show you the level of care you desperately crave.