the new incremental capabilities of the neo4j admin database import are documented correctly:
The neo4j-admin database import command has two modes:
full — used to initially import data into a non-existent empty database.
incremental — used to incrementally import data into an existing database.
but the tutorial does not reflect this:
Importing data from CSV files with
neo4j-admin database import
can only be done once into an unused database, it is used for the initial graph population only.