No, it's probably not a true story. Usually, in Roblox, such names and concepts are made up for the fun and entertainment of the players and don't have a basis in reality.
I'm not sure specifically what the 'John Doe Sad Roblox Story' is. It could be about a player named John Doe who had a bad experience in Roblox. Maybe he lost all his in - game items, or was bullied by other players in the Roblox world.
It could be that John Doe was part of a Roblox group that he really liked. He was very active in it and contributed a lot. But then, for some unjust reason, he was kicked out of the group. This sudden expulsion made him feel sad and betrayed, which could be the main plot of the sad story.
Well, usually when we hear 'John Doe', it's more of a fictional or anonymous reference. But there might be rare cases where it refers to an actual person if it's in a very specific and local context that we don't know about.