Linux doesn't really have to since 99% of users use distributions, not LFS.
And there's a difference between gratuitous (or almost gratuitous) dependencies and must have ones. From what I read in the other comments Neo4J doesn't feel like a must-have for this project.
Plus, to be honest, Mongo, Neo4J, Redis AND Elastic Search? That's got to be overkill :)
What about other OSS project? It's also not easy to make Linux from scratch. Being OSS doesn't mean it will be single click to run your instance.