I think being remembered means that our existence has left a mark on someone else’s life. Even if our encounter was brief, it proves that we were once genuinely part of each other’s stories.
If there really were a city built by those who have been forgotten, I believe its people deserve sympathy rather than criticism. After all, everyone has a story of their own, and everyone has reasons that others may never understand.
As for the boundary between being remembered and being erased, I think it lies in whether we were ever treated with sincerity. Memories may fade, and names may become blurred, but what once happened does not lose its meaning simply because no one speaks of it anymore.